Answer is Option (3) for SSC CGL Chemistry MCQ

Commercial nitric acid has a brown colour due to dissolved NO₂ . The procedure of bubbling dry air through warm commercial nitric acid, is to drive away the dissolved nitrogen dioxide so that the acid becomes colourless.

Answer is Option (3) for SSC CGL Chemistry MCQ

A growth fertilizer will have a high N content and relatively low P and K content. Ammonium nitrate is the highest Nitrogen fertilizer you can buy, and it is potent stuff. It is usually rated as 33-0-0 or 34-0-0. The bag contains 33% or 34% Nitrogen and the other 66% or 67% is inert material. Other formulations of growth fertilizers will contain 5, 6 or even 7 times more Nitrogen than anything else.

Answer is Option (4) for SSC CGL Chemistry MCQ

Since water and carbon dioxide are both compounds which contain oxygen, it is possible to obtain oxygen from either. The oxygen produced from photosynthesis is not released into the air. It is not until cellular respiration that oxygen is released. The oxygen comes from water. The water molecules are split at the “beginning” of photosynthesis for the electrons. These electrons eventually make their way to the electron transport chain, where oxygen is the final electron accept, and then released into the air. Scientists agree that there’s oxygen from ocean plants in every breath we take. Most of this oxygen comes from tiny ocean plants – called phytoplankton – that live near the water’s surface and drift with the currents. Like all plants, they photosynthesize – that is, they use sunlight and carbon dioxide to make food. A byproduct of photosynthesis is oxygen.

Answer is Option (1) for SSC CGL Chemistry MCQ

Ethylene can promote ripening in tomatoes, bananas, citrus, pineapples, dates, persimmons, pears, apples, melons, mangos, avocados, papayas and jujubes – a clear indication that the action of ethylene is general and widespread amongst a number of fruits. It is clear that ethylene is a ripening hormone – a chemical substance produced by fruits with the specific biological phenomenon of accelerating the normal process of fruit maturation and senescence.

Answer is Option (2) for SSC CGL Chemistry MCQ

Fertilizer (or fertiliser) is any organic or inorganic material of natural or synthetic origin (other than liming materials) that is added to a soil to supply one or more plant nutrients essential to the growth of plants. The three elements most needed in common fertilisers are Nitrogen. Potassium and Phosphorous.

Answer is Option (3) for SSC CGL Chemistry MCQ

The history of car pollution has been one of air and water contamination followed by regulated improvement. Cars and trucks cause a lot of air the pollution in the world today, and contribute a lot to the most common and dangerous air pollutants. About 2.3 million tons of lead in lead acid (PbA) batteries is on the road now. Over 1 million tons of lead is used in making new batteries each year. In the past, motor vehicles were the biggest source of lead. But since leaded gasoline has been phased out, lead emissions have decreased by about 98 percent. Today, metal processing is the biggest source of atmospheric lead. The highest air concentrations are found in the vicinity of ferrous and nonferrous smelters and battery manufacturers.

Answer is Option (2) for SSC CGL Chemistry MCQ

Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula NaHCO₃. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slightly salty, alkaline taste resembling that of washing soda (sodium carbonate). Since it has long been known and is widely used, the salt has many related names such as baking soda, bread soda, cooking soda, and bicarbonate of soda.

Answer is Option (2) for SSC CGL Chemistry MCQ

An atomic pile is a nuclear reactor that uses controlled nuclear fission to generate energy. The most common reactor consists of a large assembly of graphite (an allotropic form of carbon) blocks having rods of uranium metal (fuel).

Answer is Option (2) for SSC CGL Chemistry MCQ

A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Milk is an emulsified colloid of liquid butterfat globules dispersed within a water-based solution.

Answer is Option (3) for SSC CGL Chemistry MCQ

The fermentation of sugar into ethanol is one of the earliest biotechnologies employed by humanity. Fermentation of fermentable sugars by suitable yeast produces ethanol (ethyl alcohol). Yeast is a single celled fungus containing a number of enzymes useful during fermentation. Brewers yeast and wine yeast, for example, contain zymase, an enzyme that can convert glucose to ethanol.

Answer is Option (3) for SSC CGL Chemistry MCQ

Silk is a natural protein fibre, some forms of which can be woven into textiles. The protein fibre of silk is composed mainly of fibroin and produced by certain insect larvae to form cocoons. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyxmorireared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colours.

Answer is Option (3) for SSC CGL Chemistry MCQ

Portions of the development and history of the hydrogen bomb remain classified. But it is public knowledge that its chief architect was Dr. Edward Teller. The first H bomb (or thermonuclear bomb / fusion bomb) detonated was on November 1, 1952 in Enewetak in the Marshall Islands. The hydrogen bomb is also called the Teller-Ulam design, after Edward Teller and Stanislaw Ulam who helped in the project too.

Answer is Option (2) for SSC CGL Chemistry MCQ

In the case of two electrons occupying the same orbital, the Pauli principle demands that they have opposite spin. The Pauli Exclusion Principle is the quantum mechanical principle that no two identical fermions (particles with half-integer spin) may occupy the same quantum state simultaneously. A more rigorous statement is that the total wave function for two identical fermions is anti-symmetric with respect to exchange of the particles.

Answer is Option (1) for SSC CGL Chemistry MCQ

Galvanization is the process of applying a protective zinc coating to steel or iron, in order to prevent rusting. The term is derived from the name of Italian scientist Luigi Galvani. Although galvanization can be done with electrochemical and electro-deposition processes, the most common method in current use is hot-dip galvanization, in which steel parts are submerged in a bath of molten zinc.

Answer is Option (3) for SSC CGL Chemistry MCQ

Milk contains a sugar called lactose, a disaccharide (compound sugar) made by the glycosidic bonding between glucose and glactose (monosaccharides). When milk is heated to a temperature of 30-40 degrees centigrade and a small amount of old curd added to it, the lactobacillus in that curd sample gets activated and multiplies. These convert the lactose into lactic acid, which imparts the sour taste to curd.

Answer is Option (3) for SSC CGL Chemistry MCQ

Hydrocarbons are organic compounds containing carbon and hydrogen and found in crude oil and natural gas. Hydrocarbons are formed from the remains of marine animals and plants that lived in shallow inland seas, died, and drifted to the bottom. The term petroleum is used as a common denotation for crude oil (mineral oil) and natural gas, i.e., the hydrocarbons from which various oil and gas products are made.

Answer is Option (1) for SSC CGL Chemistry MCQ

There are six (6) protons in Carbon-12. The 12 refers to the number of protons plus the number of neutrons. There are 6 of each in carbon-12. The number of protons in the nucleus of an atom determines an element’s atomic number. The mass number of an element is the total of number of neutrons and number of protons.

Answer is Option (2) for SSC CGL Chemistry MCQ

J. (Julius) Robert Oppenheimer was born in New York City on April 22, 1904. Under Oppenheimer’s guidance, the laboratories at Los Alamos were constructed. There, he brought the best minds in physics to work on the problem of creating an atomic bomb. In the end, he was managing more than 3,000 people, as well as tackling theoretical and mechanical problems that arose. He is often referred to as the “father” of the atomic bomb.

Answer is Option (3) for SSC CGL Chemistry MCQ

A fluorescent lamp or fluorescent tube is a gasdischarge lamp that uses electricity to excite mercury vapour. it contains mercury vapour and argon. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful light more efficiently than an incandescent lamp.

Answer is Option (4) for SSC CGL Chemistry MCQ

Magnesium hydroxide is an inorganic compound with the chemical formula Mg (OH)₂ . As a suspension in water, it is often called milk of magnesia because of its milk-like appearance. The solid mineral form of magnesium hydroxide is known as brucite. Magnesium hydroxide is a common component of antacids and laxatives; it interferes with the absorption of folic acid and iron. Magnesium hydroxide has low solubility in water, with a Ksp of 1.5×10^–11; however all of the magnesium hydroxide that does dissolve dissociates.

Answer is Option (4) for SSC CGL Chemistry MCQ

The most basic kind of soap is made from cuastic soda and animal fat. The two are heated together, and then cooled. The process is called “saponification”. In technical terms, saponification involves base (usually caustic soda NaOH) hydrolysis of triglycerides, which are esters of fatty acids, to form the sodium salt of a carboxylate.

Answer is Option (4) for SSC CGL Chemistry MCQ

Quartz is an abundant mineral in the Earth’s continental crust. It is made up of a continuous framework of SiO₄ silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO₂ . There are many different varieties of quartz, several of which are semiprecious gemstones. Most quartz used in microelectronics is produced synthetically. Large, flawless and un-twinned crystals are produced in an autoclave via the hydrothermal process. The process involves treating crushed natural quartz with hot aqueous solution of a base such as sodium hydroxide.

Answer is Option (4) for SSC CGL Chemistry MCQ

A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Cloud is a colloidal dispersion of Water drops in a dispersion medium of air.

Answer is Option (3) for SSC CGL Chemistry MCQ

Waxes are a class of chemical compounds that are plastic (malleable) near ambient temperatures. Characteristically, they melt above 45 °C (113 °F) to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, non-polar solvents. All waxes are organic compounds, both synthetic and naturally occurring. Although most natural waxes are esters, paraffin waxes are hydrocarbons, Paraffin waxes are mixtures of saturated and iso-alkanes, naphthene’s, and alkyl- and naphthene-substituted aromatic compounds.

Answer is Option (3) for SSC CGL Chemistry MCQ

Peat contains recognizable traces of the original plant material. Initially the peat is converted into lignite or ‘brown coal’ – these are coal-types with low organic maturity. In comparison to other coals, lignite is quite soft and its colour can range from dark black to various shades of brown.

Answer is Option (4) for SSC CGL Chemistry MCQ

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element (by mass) forming the planet Earth as a whole, forming much of Earth’s outer and inner core. It is the fourth most common element in the Earth’s crust. Wrought iron is the purest form of iron. It contains less than 0.25% carbon.

Answer is Option (4) for SSC CGL Chemistry MCQ

Alloy obtained after mixing mercury with another metal is called Amalgam. All metals but Iron, Platinum, Tungsten and Tantalum form Amalgam with mercury. Silver and gold amalgams are used to fill tooth cavities in dentistry. Metallic bonds (arising out of electrostatic forces) hold the metals together in amalgam.

Mercury is a transition metal present in period 6 and group 12 of the periodic table with 80 as the atomic number. Mercury is the only metal, which is liquid at room temperature. When placed in a tube meniscus of mercury is convex, opposite to concave meniscus of water. It is used in clinical thermometers because of the property of its proportional expansion with increasing temperature. Elemental mercury is toxic to living beings and Minamata disease is associated with its consumption.

Tin: Tin is a chemical element with the symbol Sn and atomic number 50. It is a silvery metal that is soft enough to be cut with little force.

Lead: Lead is a chemical element with the symbol Pb and atomic number 82. It is a heavy metal.

Zinc: Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature.

Answer is Option (3) for SSC CGL Chemistry MCQ

Sulphonate is a detergent used for cleaning clothes and utensils. It is a salt or ester of any sulphonic acid containing the ion RSO₂ ^– or the group RSO₂ ^– , R being an organic group, it is used as comonomers in LLDPE and HDPE (C4–C8), in manufacture of lubricants and industrial chemicals and plasticisers.

Answer is Option (4) for SSC CGL Chemistry MCQ

Uranium–lead (U–Pb) dating is one of the oldest and most refined of the radiometric dating schemes, with a routine age range of about 1 million years to over 4.5 billion years, and with routine precisions in the 0.1–1 percent range. The method relies on two separate decay chains, the uranium series from 238U to 206Pb, with a half-life of 4.47 billion years and the actinium series from 235U to 207Pb, with a half-life of 704 million years. These decay routes occur via a series of alpha (and beta) decays, in which 238U with daughter nuclides undergo eight total alpha and six beta decays whereas 235U with daughters only experience seven alpha and four beta decays. The existence of two ‘parallel’ uranium-lead decay routes ( 238U to 206Pb and 235U to 207Pb) leads to multiple dating techniques within the overall U–Pb system. The term U–Pb dating normally implies the coupled use of both decay schemes in the ‘concordia diagram’.

Answer is Option (4) for SSC CGL Chemistry MCQ

A smoke bomb is a firework designed to produce smoke upon ignition. Smoke bombs are useful to military units, airsoft games, paintball games, selfdefense and pranks. The smoke bomb was first created in 1848, by the inventor Robert Yale. He developed 17th century Chinese-style fireworks and later modified the formula to produce more smoke for a longer period of time. Coloured smoke devices use a formula that consists of an oxidizer (typically potassium chlorate, KClO₃), a fuel (generally sugar), a moderant (such as sodium bicarbonate) to keep the reaction from getting too hot, and a powdered organic dye. The burning of this mixture evaporates the dye and forces it out of the device, where it condenses in the atmosphere to form a “smoke” of finely dispersed particles. A smoke ball is a hollow, cherry-sized sphere of brightly coloured clay or cardboard filled with a smoke-generating composition that produces a forceful jet of coloured smoke for 10 to 15 seconds.

Answer is Option (3) for SSC CGL Chemistry MCQ

Nickel silver, also known as German silver, Argentan, new silver, nickel brass, albata, alpacca, or electrum, is a copper alloy with nickel and often zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver is named for its silvery appearance, but it contains no elemental silver unless plated. The name “German silver” refers to its development by 19th-century German metalworkers in imitation of the Chinese alloy known as paktong (Cupronickel) All modern, commercially important nickel silvers (such as those standardized under ASTM B122) contain significant amounts of zinc, and are sometimes considered a subset of brass. It is used in zippers, better-quality keys, costume jewellery, for making musical instruments (e.g., cymbals, saxophones), and is preferred for the track in electrically powered model railway layouts, as its oxide is conductive. It is widely used in the production of coins (e.g. Portuguese escudo and the former GDR marks,). Its industrial and technical uses include marine fittings and plumbing fixtures for its corrosion resistance, and heating coils for its high electrical resistance.

Answer is Option (2) for SSC CGL Chemistry MCQ

Copper forms a rich variety of compounds with oxidation states +1 and +2, which are often called cuprous and cupric, respectively. It does not react with water, but it slowly reacts with atmospheric oxygen forming a layer of brown-black copper oxide. In contrast to the oxidation of iron by wet air, this oxide layer stops the further, bulk corrosion. A green layer of verdigris (copper carbonate) can often be seen on old copper constructions, such as the Statue of Liberty, the largest copper statue in the world built using repoussé and chasing. Hydrogen sulfides and sulfides react with copper to form various copper sulfides on the surface. In the latter case, the copper corrodes, as is seen when copper is exposed to air containing sulfur compounds. Oxygen-containing ammonia solutions give water-soluble complexes with copper, as do oxygen and hydrochloric acid to form copper chlorides and acidified hydrogen peroxide to form copper(II) salts. Copper(II) chloride and copper combine to form copper(I) chloride.

Answer is Option (2) for SSC CGL Chemistry MCQ

A rechargeable battery, storage battery, or accumulator is a type of electrical battery. It comprises one or more electrochemical cells, and is a type of energy accumulator. It is known as a secondary cell because its electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging from button cells to megawatt systems connected to stabilize an electrical distribution network. Several different combinations of chemicals are commonly used, including: lead–acid, nickel cadmium (NiCd), nickel metal hydride (NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer). Rechargeable batteries have lower total cost of use and environmental impact than disposable batteries. Some rechargeable battery types are available in the same sizes as disposable types. Rechargeable batteries have higher initial cost, but can be recharged very cheaply and used many times.

Answer is Option (4) for SSC CGL Chemistry MCQ

A colloidal dispersion in which the dispersed particles are more or less liquid and exert a certain attraction on and absorb a certain quantity of the fluid in which they are suspended is called as hydrophilic colloid. Molecules of a hydrophilic colloid have an affinity for water molecules and when dispersed in water become hydrated. Hydrated colloids swell and increase the viscosity of the system, thereby improving stability by reducing the interaction between particles and their tendency to settle. They may also possess a net surface electrical charge. The charge sign depends on the chemical properties of the colloid and the pH of the system. The presence of a surface charge produces repulsion of the charged particles and thus reduces the likelihood that the particles will adhere to one another and settle. Some examples of hydrophilic colloids used in pharmacy are acacia, methylcellulose, and proteins, such as gelatin and albumin.

Answer is Option (2) for SSC CGL Chemistry MCQ

When formaldehyde and potassium hydroxide are heated, we get methyl alcohol and formic acid. it is cannizarroo reaction. The Cannizzaro reaction, named after its discoverer Stanislao Cannizzaro, is a chemical reaction that involves the base-induced disproportionation of an aldehyde. Cannizzaro first accomplished this transformation in 1853, when he obtained benzyl alcohol and potassium benzoate from the treatment of benzaldehyde with potash (potassium carbonate). More typically, the reaction would be conducted with sodium or potassium hydroxide. The oxidation product is a salt of a carboxylic acid and the reduction product is an alcohol.

Answer is Option (3) for SSC CGL Chemistry MCQ

when concentrated hydrosulphuric acid is added to dry potassium nitrate brown fumes are evolved and these fumes are evolved due to the formation of nitrogen dioxide. Nitrogen dioxide is the chemical compound with the formula NO₂. It is one of several nitrogen oxides. NO₂ is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year. This reddish-brown toxic gas has a characteristic sharp, biting odour and is a prominent air pollutant. Nitrogen dioxide is a paramagnetic and bent molecule.

Answer is Option (4) for SSC CGL Chemistry MCQ

Melamine-formaldehyde resin or melamine is used in the manufacture of plastic crockery. Melamine resin or melamine formaldehyde (also shortened to melamine) is a hard, thermosetting plastic material made from melamine and formaldehyde by polymerization. Melamine resin is often used in kitchen utensils and plates (such as Melmac). Melamine resin utensils and bowls are not microwave safe. As with all thermosetting materials, melamine resin cannot be melted and, therefore, cannot be recycled through melting.

Answer is Option (1) for SSC CGL Chemistry MCQ

Vulcanization is a chemical process for converting rubber or related polymers into more durable materials via the addition of sulfur or other equivalent “curatives” or “accelerators”. These additives modify the polymer by forming crosslinks (bridges) between individual polymer chains. Vulcanized materials are less sticky and have superior mechanical properties. A vast array of products are made with vulcanized rubber including tires, shoe soles, hoses, and hockey pucks. The process is named after Vulcan, Roman god of fire. Hard vulcanized rubber is sometimes sold under the brand names ebonite or vulcanite, and is used to make hard articles such as bowling balls and saxophone mouth pieces.

Answer is Option (2) for SSC CGL Chemistry MCQ

Radiocarbon dating (usually referred to as simply carbon dating) is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 ( ¹⁴C) to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e., uncalibrated, radiocarbon ages are usually reported in radiocarbon years “Before Present” (BP), with “present” defined as CE 1950. Such raw ages can be calibrated to give calendar dates. One of the most frequent uses of radiocarbon dating is to estimate the age of organic remains from archaeological sites.

Answer is Option (4) for SSC CGL Chemistry MCQ

Water is not effective in extinguishing a fire caused by petrol because water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn. The specific gravity (or relative density) of gasoline ranges from 0.71–0.77 kg/l (719.7 kg/m³) while the specific gravity of water is 1000 kg/m³ and that is why gasoline or petrol floats on the upper surface of the water. Water cannot generally be used to extinguish a gasoline fire, unless used in a fine mist.

Answer is Option (3) for SSC CGL Chemistry MCQ

Because of the Archimedes’ principle, a lifting gas is required for aerostats to create buoyancy. Its density is lower than that of air (about 1.29 kg/m³, 1.29 g/ L). Only certain lighter than air gases are suitable as lifting gases. Hydrogen and helium are the most commonly used lift gases. Although helium is twice as heavy as (diatomic) hydrogen, they are both so much lighter than air that this difference is inconsequential. Both provide about 9.8 N of lift (1 Newton is the force required to accelerate 1 kg at 1 m/sec²) per cubic meter of gas at STP. Helium is the second lightest gas. For that reason, it is an attractive gas for lifting as well. A major advantage is that this gas is noncombustible. Today helium is used instead of hydrogen, since it is inert so non-flammable which makes things a lot safer. Hydrogen can ignite very easily when mixed with the oxygen of the surrounding air.

Answer is Option (1) for SSC CGL Chemistry MCQ

Ripening is a process in fruits that causes them to become more palatable. In general, a fruit becomes sweeter, less green, and softer as it ripens. Even though the acidity of fruit increases as it ripens, the higher acidity level does not make the fruit seem tarter, which can lead to the misunderstanding that the riper the fruit the sweeter. Ripening agents speed up the ripening process. They allow many fruits to be picked prior to full ripening, which is useful, since ripened fruits do not ship well. For example, bananas are picked when green and artificially ripened after shipment by being gassed with ethylene. Calcium carbide is also used for ripening fruit artificially in some countries. Calcium carbide reacts with water to produce acetylene, which acts as an artificial ripening agent. Industrial-grade calcium carbide may contain traces of arsenic and phosphorus which makes it a human health concern. The use of this chemical for this purpose is illegal in most countries.

Answer is Option (4) for SSC CGL Chemistry MCQ

Aluminium forms one stable oxide, known by its mineral name corundum. Sapphire and ruby are impure corundum contaminated with trace amounts of other metals. Corundum is a crystalline form of aluminium oxide (Al₂O₃) with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally clear transparent materials, but can have different colours when impurities are present. Transparent specimens are used as gems, called ruby if red and padparadscha if pink-orange. All other colours are called sapphire, e.g., “green sapphire” for a green specimen. Because of corundum’s hardness (pure corundum is defined to have 9.0 Mohs), it can scratch almost every other mineral. It is commonly used as an abrasive, on everything from sandpaper to large machines used in machining metals, plastics, and wood. Some emery is a mix of corundum and other substances, and the mix is less abrasive, with an average hardness near 8.0.

Answer is Option (1) for SSC CGL Chemistry MCQ

Liquid hydrogen (LH₂) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H₂ form. To exist as a liquid, H₂ must be cooled below hydrogen’s critical point of 33 K. However, for hydrogen to be in a full liquid state without evaporating at atmospheric pressure, it needs to be cooled to 20.28 K (-423.17 °F/-252.87°C). One common method of obtaining liquid hydrogen involves a compressor resembling a jet engine in both appearance and principle. Liquid hydrogen is typically used as a concentrated form of hydrogen storage.

Answer is Option (3) for SSC CGL Chemistry MCQ

Gunpowder, also known since the late 19th century as black powder, was the first chemical explosive and the only one known until the mid-1800s. It is a mixture of sulfur, charcoal, and potassium nitrate (saltpetre)— with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer. Because of its burning properties and the amount of heat and gas volume that it generates, gunpowder has been widely used as a propellant in firearms and as a pyrotechnic composition in fireworks. Gunpowder is classified as a low explosive because of its relatively slow decomposition rate and consequently low brisance. Low explosives deflagrate at subsonic speeds, whereas high explosives detonate, producing a supersonic wave. Ignition of the powder packed behind a bullet must generate enough pressure to force it from the muzzle at high speed, but not enough to rupture the gun barrel. Gunpowder is thus less suitable for shattering rock or fortifications.

Answer is Option (3) for SSC CGL Chemistry MCQ

A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid (water or gas), which runs through turbines that power either ship’s propellers or generators. Some produce isotopes for medical and industrial use, and some are run only for research. In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235. Commonly used moderators include regular (light) water (roughly 75% of the world’s reactors), solid graphite (20% of reactors) and heavy water (5% of reactors). Beryllium has also been used in some experimental types, and hydrocarbons have been suggested as another possibility.

Answer is Option (2) for SSC CGL Chemistry MCQ

An atomic clock is a clock device that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element. Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS. The principle of operation of an atomic clock is not based on nuclear physics, but rather on atomic physics and using the microwave signal that electrons in atoms emit when they change energy levels. Early atomic clocks were based on masers at room temperature. Currently, the most accurate atomic clocks first cool the atoms to near absolute zero temperature by slowing them with lasers and probing them in atomic fountains in a microwave-filled cavity. The first accurate atomic clock, a caesium standard based on a certain transition of the caesium-133 atom, was built by Louis Essen in 1955 at the National Physical Laboratory in the UK. Calibration of the caesium standard atomic clock was carried out by the use of the astronomical time scale ephemeris time (ET).

Answer is Option (3) for SSC CGL Chemistry MCQ

The light-sensitive chemicals used in photographic film and paper are silver halides. Silver halides are used in photographic film and photographic paper, including graphic art film and paper, where silver halide crystals in gelatin are coated on to a film base, glass or paper substrate. When a silver halide crystal is exposed to light, a sensitivity speck on the surface of the crystal is turned into a small speck of metallic silver (these comprise the invisible or latent image). If the speck of silver contains approximately four or more atoms, it is rendered developable – meaning that it can undergo development which turns the entire crystal into metallic silver. Areas of the emulsion receiving larger amounts of light (reflected from a subject being photographed, for example) undergo the greatest development and therefore results in the highest optical density. Silver halides are also used to make corrective lenses darken when exposed to ultraviolet light.

Answer is Option (4) for SSC CGL Chemistry MCQ

Tetraethyl lead was extensively used as an additive to gasoline, wherein it served as an effective antiknock agent and prevented exhaust valve and seat wear. The use of TEL in gasoline started in the US, while in Europe, alcohol was initially used. The advantages of leaded gasoline — its higher energy content and storage quality — eventually led to a universal switch to leaded fuel. One of the greatest advantages of TEL over other antiknock agents or the use of high-octane blend stocks is the very low concentrations needed. Typical formulations called for 1 part of prepared TEL to 1260 parts untreated gasoline. Competing antiknock agents must be used in greater amounts, often reducing the energy content of the gasoline. TEL is highly soluble in gasoline, ethanol is poorly soluble, and that solubility decreases as fuel humidity increases. Over time, droplets and pools of water can form in the fuel system creating a risk of fuel line icing.

Answer is Option (1) for SSC CGL Chemistry MCQ

U²³⁵ is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope U²³⁸ it is fissile, i.e., it can sustain fission chain reaction. It is the only fissile isotope that is a primordial nuclide or found in significant quantity in nature. If at least one neutron from U²³⁵ fission strikes another nucleus and causes it to fission, then the chain reaction will continue. If the reaction will sustain itself, it is said to be critical, and the mass of U²³⁵ required to produce the critical condition is said to be a critical mass. A critical chain reaction can be achieved at low concentrations of U²³⁵ if the neutrons from fission are moderated to lower their speed, since the probability for fission with slow neutrons is greater. In nuclear reactors, the reaction is slowed down by the addition of control rods which are made of elements such as boron, cadmium, and hafnium which can absorb a large number of neutrons. In nuclear bombs, the reaction is uncontrolled and the large amount of energy released creates a nuclear explosion.

Answer is Option (4) for SSC CGL Chemistry MCQ

Nucleon is one of the particles that makes up the atomic nucleus. Each atomic nucleus consists of one or more nucleons, and each atom in turn consists of a cluster of nucleons surrounded by one or more electrons. There are two kinds of nucleon: the neutron and the proton. The mass number of a given atomic isotope is identical to its number of nucleons. Thus the term nucleon number may be used in place of the more common terms mass number or atomic mass number. Until the 1960s, nucleons were thought to be elementary particles, each of which would not then have been made up of smaller parts. Now they are known to be composite particles, made of three quarks bound together by the so-called strong interaction. The interaction between two or more nucleons is called inter-nucleon interactions or nuclear force, which is also ultimately caused by the strong interaction. (Before the discovery of quarks, the term “strong interaction” referred to just inter-nucleon interactions).

Answer is Option (1) for SSC CGL Chemistry MCQ

Pencils create marks via physical abrasion, leaving behind a trail of solid core material that adheres to a sheet of paper or other surface. They are noticeably distinct from pens, which dispense liquid or gel ink that stain the light colour of the paper. Most pencil cores are made of graphite mixed with a clay binder, leaving grey or black marks that can be easily erased. Graphite pencils are used for both writing and drawing, and the result is durable: although writing can usually be removed with an eraser, it is resistant to moisture, most chemicals, ultraviolet radiation and natural aging. Other types of pencil core are less widely used. Charcoal pencils are mainly used by artists for drawing and sketching.

Answer is Option (2) for SSC CGL Chemistry MCQ

Lead is used in building construction, lead-acid batteries, bullets and shot, weights, as part of solders, pewters, fusible alloys, and as a radiation shield. Lead has the highest atomic number of all of the stable elements, although the next higher element, bismuth, has a half-life that is so long (much longer than the age of the universe) that it can be considered stable. Its four stable isotopes have 82 protons, a magic number in the nuclear shell model of atomic nuclei. Lead is a highly poisonous metal (regardless if inhaled or swallowed), affecting almost every organ and system in the body. The main target for lead toxicity is the nervous system, both in adults and children. Long-term exposure of adults can result in decreased performance in some tests that measure functions of the nervous system. Exposure to high lead levels can severely damage the brain and kidneys in adults or children and ultimately cause death.

Answer is Option (1) for SSC CGL Chemistry MCQ

Boron shielding is used as a control for nuclear reactors, taking advantage of its high cross-section for neutron capture. Elemental boron is rare and poorly studied because the material is extremely difficult to prepare. Most studies on “boron” involve samples that contain small amounts of carbon. Chemically, boron behaves more similarly to silicon than to aluminium. Crystalline boron is chemically inert and resistant to attack by boiling hydrofluoric or hydrochloric acid. When finely divided, it is attacked slowly by hot concentrated hydrogen peroxide, hot concentrated nitric acid, hot sulfuric acid or hot mixture of sulfuric and chromic acids. The rate of oxidation of boron depends upon the crystallinity, particle size, purity and temperature. Boron does not react with air at room temperature, but at higher temperatures it burns to form boron trioxide.

Answer is Option (4) for SSC CGL Chemistry MCQ

A thermonuclear weapon is a nuclear weapon design that uses the heat generated by a fission bomb to compress a nuclear fusion stage which indirectly results in greatly increased energy yield (i.e., bomb “power”). It is colloquially referred to as a hydrogen bomb or H-bomb because it employs hydrogen fusion, though in most applications the majority of its destructive energy comes from uranium fission, not hydrogen fusion by itself. The fusion stage in such weapons is required to efficiently cause the large quantities of fission characteristic of most thermonuclear weapons. The concept of the thermonuclear weapon was first developed and used by the United States and has since been used in most of the world’s nuclear weapons.

Answer is Option (1) for SSC CGL Chemistry MCQ

Three forms (or allotropes) of oxygen are involved in the ozone-oxygen cycle: oxygen atoms (O or atomic oxygen), oxygen gas (O₂ or diatomic oxygen), and ozone gas (O₃ or triatomic oxygen). Ozone is formed in the stratosphere when oxygen molecules photodissociate after absorbing an ultraviolet photon whose wavelength is shorter than 240 nm. This converts a single O₂ into two atomic oxygen radicals. The atomic oxygen radicals then combine with separate O₂ molecules to create two O₃ molecules. These ozone molecules absorb UV light between 310 and 200 nm, following which ozone splits into a molecule of O₂ and an oxygen atom. The oxygen atom then joins up with an oxygen molecule to regenerate ozone. This is a continuing process which terminates when an oxygen atom “recombines” with an ozone molecule to make two O₂ molecules.

Answer is Option (4) for SSC CGL Chemistry MCQ

Fiberglass is a lightweight, extremely strong, and robust material. Although strength properties are somewhat lower than carbon fiber and it is less stiff, the material is typically far less brittle, and the raw materials are much less expensive. Its bulk strength and weight properties are also very favorable when compared to metals, and it can be easily formed using molding processes.

Answer is Option (1) for SSC CGL Chemistry MCQ

Itai-itai disease was the documented case of mass cadmium poisoning in Toyama Prefecture, Japan, starting around 1912. The cadmium poisoning caused softening of the bones and kidney failure. The disease is named for the severe pains caused in the joints and spine. The cadmium was released into rivers by mining companies in the mountains. The mining companies were successfully sued for the damage. Itai-itai disease is known as one of the Four Big Pollution Diseases of Japan. Itai-itai disease was caused by cadmium poisoning due to mining in Toyama Prefecture. The cadmium and other heavy metals accumulated at the bottom of the river and in the water of the river. This water was then used to irrigate the rice fields. The rice absorbed heavy metals, especially the cadmium. The cadmium accumulated in the people eating contaminated rice.

Answer is Option (3) for SSC CGL Chemistry MCQ

Ethylene glycol (IUPAC name: ethane-1,2-diol) is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colourless, syrupy, sweettasting liquid. Ethylene glycol is toxic, and ingestion can result in death. Due to its low freezing point ethylene glycol resists freezing. A mixture of 60% ethylene glycol and 40% water freezes at -45 degree C (-49 degree F). Diethylene glycol behaves similarly. It is used as a deicing fluid for windshields and aircraft. The antifreeze capabilities of ethylene glycol have made it an important component of vitrification (anticrystallization) mixtures for low-temperature preservation of biological tissues and organs.

Answer is Option (3) for SSC CGL Chemistry MCQ

Monazite is a reddish-brown phosphate mineral containing rare earth metals. It occurs usually in small isolated crystals. There are actually at least four different kinds of monazite, depending on relative elemental composition of the mineral. Monazite is an important ore for thorium, lanthanum, and cerium. It is often found in placer deposits. The deposits in India are particularly rich in monazite. It has a hardness of 5.0 to 5.5 and is relatively dense, about 4.6 to 5.7 g/ cm3. Because of the presence of thorium within monazite, it can be radioactive. If samples are kept, they should be placed away from minerals that can be damaged by radiation. Because of its radioactive nature, the monazite within rocks is a useful tool for dating geological events, such as heating or deformation of the rock.

Answer is Option (1) for SSC CGL Chemistry MCQ

A sodium-vapor lamp is a gas-discharge lamp that uses sodium in an excited state to produce light. There are two varieties of such lamps: low pressure and high pressure. Low-pressure sodium lamps are the most efficient electrical light sources, but their yellow light restricts applications to outdoor lighting such as street lamps. High-pressure sodium lamps have a broader spectrum of light but poorer colour rendering than other types. Because sodium vapor lamps cause less light pollution than mercury-vapor lamps, many cities that have large astronomical observatories employ them.

Answer is Option (1) for SSC CGL Chemistry MCQ

Vulcanization is a chemical process for converting rubber or related polymers into more durable materials via the addition of sulfur or other equivalent “curatives” or “accelerators”. By far the most common vulcanizing methods depend on sulfur.

Answer is Option (3) for SSC CGL Chemistry MCQ

Older clear-glass Pyrex manufactured by Corning before 1998, Arc International’s Pyrex products, and Pyrex laboratory glassware is made of borosilicate glass. According to the National Institute of Standards and Technology, borosilicate Pyrex is composed of (as percentage of weight): 14% boron, 51% oxygen, 0.3% sodium, 1% aluminium, 38% silicon, and less than 1% potassium. Pyrex glass cookware manufactured by World Kitchen is made of tempered soda-lime glass instead of borosilicate. World Kitchen justified this change by stating that soda-lime glass was cheaper to produce, is the most common form of glass used in bakeware in the US, and that it also had higher mechanical strength than borosilicate— making it more resistant to breakage when dropped, which it believed to be the most common cause of breakage in glass bakeware.

Answer is Option (4) for SSC CGL Chemistry MCQ

LOX and liquid hydrogen, used in the Space Shuttle orbiter, the Centaur upper stage of the Atlas V, Saturn V upper stages, the newer Delta IV rocket, the H-IIA rocket, and most stages of the European Ariane rockets. Liquid fueled rockets have higher specific impulse than solid rockets and are capable of being throttled, shut down, and restarted. Only the combustion chamber of a liquid fueled rocket needs to withstand high combustion pressures and temperatures and they can be regeneratively cooled by the liquid propellant. For these reasons, most orbital launch vehicles use liquid propellants. The primary performance advantage of liquid propellants is due to the oxidizer. Several practical liquid oxidizers (liquid oxygen, nitrogen tetroxide, and hydrogen peroxide) are available which have better specific impulse than the ammonium perchlorate used in most solid rockets, when paired with comparable fuels.

Answer is Option (3) for SSC CGL Chemistry MCQ

Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates, the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO₂ shall not be less than 2.0. The magnesium oxide content (MgO) shall not exceed 5.0% by mass. Cement sets when mixed with water by way of a complex series of chemical reactions still only partly understood. The different constituents slowly crystallise and the interlocking of their crystals gives cement its strength. Carbon dioxide is slowly absorbed to convert the portlandite (Ca(OH)₂) into insoluble calcium carbonate. After the initial setting, immersion in warm water will speed up setting. Gypsum is added as an inhibitor to prevent flash setting.

Answer is Option (4) for SSC CGL Chemistry MCQ

Lead is a naturally occurring bluish-gray metal found in small amounts in the earth’s crust. In the past, when lead was added to gasoline, breathing automobile exhaust was the major source of lead exposure for most people. Lead in the exhaust also contaminated the soil near roads. Another major source of exposure is old paint that contains lead. Lead has been found to be carcinogen. A substance that causes cancer or helps cancer grow is called a carcinogen. Several studies have looked for a link between exposure to lead in the workplace (mainly among battery workers and smelter workers) and lung cancer. Some of these studies have found a small increase in lung cancer risk. Studies have also looked at possible links between workplace exposures to lead and other cancers, including cancers of the brain, kidney, bladder, colon, and rectum.

Answer is Option (2) for SSC CGL Chemistry MCQ

The term hardened steel is often used for a medium or high carbon steel that has been given the heat treatments of quenching followed by tempering. The quenching results in the formation of metastable martensite, the fraction of which is reduced to the desired amount during tempering. This is the most common state for finished articles such as tools and machine parts. In contrast, the same steel composition in annealed state will be softer as required for forming and machining. Carbon steels which can successfully undergo heat-treatment have carbon content in the range of 0.30–1.70% by weight. Trace impurities of various other elements can have a significant effect on the quality of the resulting steel. Trace amounts of sulfur in particular make the steel red-short.

Answer is Option (2) for SSC CGL Chemistry MCQ

Cement is made by heating limestone (calcium carbonate) with small quantities of other materials (such as clay) to 1450 degree C in a kiln, in a process known as calcination, whereby a molecule of carbon dioxide is liberated from the calcium carbonate to form calcium oxide, or quicklime, which is then blended with the other materials that have been included in the mix. The resulting hard substance, called ‘clinker’, is then ground with a small amount of gypsum into a powder to make ‘Ordinary Portland Cement’, the most commonly used type of cement (often referred to as OPC). Portland cement is a basic ingredient of concrete, mortar and most non-specialty grout. The most common use for Portland cement is in the production of concrete.

Answer is Option (2) for SSC CGL Chemistry MCQ

Glass is an amorphous (non-crystalline) solid material. Glasses are typically brittle and optically transparent. The standard definition of a glass (or vitreous solid) is a solid formed by rapid melt quenching. However, the term glass is often used to describe any amorphous solid that exhibits a glass transition temperature Tg. If the cooling is sufficiently rapid (relative to the characteristic crystallization time) then crystallization is prevented and instead the disordered atomic configuration of the super-cooled liquid is frozen into the solid state at Tg. Generally, the structure of a glass exists in a meta-stable state with respect to its crystalline form.

Answer is Option (2) for SSC CGL Chemistry MCQ

Flames are formed when a fuel gas, like acetylene, reacts with a support gas such as oxygen. This reaction creates a lot of heat and light, which we see as a flame. An oxygen acetylene flame can create temperatures over 3200°C. Pure oxygen, instead of air (20% oxygen/80% nitrogen), is used to increase the flame temperature to allow localized melting of the work piece material (e.g. steel) in a room environment. A common propane/air flame burns at about 3,630 degree F (2,000 degree C), a propane/ oxygen flame burns at about 4,530 degree F (2,500 degree C), and an acetylene/oxygen flame burns at about 6,330 degree F (3,500 degree C).

Answer is Option (2) for SSC CGL Chemistry MCQ

Dichlorodifluoromethane (R-12), is a colourless gas, and usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane (CFC), used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, its manufacture was banned in the United States along with many other countries in 1994 due to concerns about damage to the ozone layer. It is soluble in many organic solvents. It can be prepared by reacting carbon tetrachloride with hydrogen fluoride in the presence of a catalytic amount of antimony pentachloride. This reaction can also produce trichlorofluoromethane (CCl₃ F), chlorotrifluoromethane (CClF₃) and tetrafluoromethane (CF₄).

Answer is Option (1) for SSC CGL Chemistry MCQ

Electric fuse:

An electrical safety device that is used to protect the electrical circuit from overloads is called a fuse. The material used for fuse elements must be of:

• low melting point,
• low ohmic loss,
• high resistivity,
• low cost
• free from detraction.

The material used for making fuse elements has a low melting point such as tin, lead, or zinc.

A low melting point is, however, available with a high specific resistance metal.

The material mainly used for fuse elements are tin, lead, silver, copper, zinc, aluminum, and an alloy of lead and tin

Hence from the given explanation above, an electrical fuse must have high resistivity to avoid loss of current and low melting point so that in case of short-circuit, Fuse wire will melt with a slight change in temperature.

Answer is Option (3) for SSC CGL Chemistry MCQ

Artificial rain is produced by seeding clouds with Silver Iodide. Cloud seeding is the process of making precipitation fall using substances like dry ice, and silver iodide.

Cloud seeding is an artificial way to create moisture in the clouds so as to cause rainfall. Chemicals used for cloud seeding are silver iodide, potassium iodide, and dry ice.

Answer is Option (2) for SSC CGL Chemistry MCQ

Physically most of the non-metals in our environment exist as gases, solids that are brittle and lack lustre. For example, at room temperature hydrogen, oxygen are gases whereas sulphur and phosphorous exist as solids.

Bromine is the only non-metal that exists in liquid form at room temperature (40 °C) because its intermolecular force is strong enough to prevent it from evaporating.

Answer is Option (1) for SSC CGL Chemistry MCQ

In silvery paints, the main constituent is aluminium powder because of lustrous similarity to white silver.

Answer is Option (3) for SSC CGL Chemistry MCQ

Gases which absorb outgoing terrestrial radiation are called greenhouse gases, such as water vapour, methane, chloro-fluorocarbons, and carbon dioxide.

Answer is Option (2) for SSC CGL Chemistry MCQ

Brass gets discoloured in air because of Hydrogen sulphide. Transition elements are coloured. The brass is combination of Zn and Cu. But it is discoloured due to hydrogen sulphide in air.

Answer is Option (4) for SSC CGL Chemistry MCQ

The foot of the common mussel (Mytilus edulis) produces a sticky glue due to a unique compound called mussel adhesive protein, which contains a high concentration of an amino acid, DOPA (dihydroxyphenylalanine), which can cling to wet surfaces with extraordinary strength. Besides heart implants, the compound could be used as a tooth coating to prevent dental plaque, which is caused by bacterial infection.

Answer is Option (2) for SSC CGL Chemistry MCQ

Nitrogen is a major constituent of all proteins, and thus of all living organisms. The deficiency of nitrogen causes yellowing of older leaves, stunted plants, dormancy of lateral buds, purple colouration in shoot axis surface, wrinkling of cereal grains and inhibition of cell division.

Answer is Option (4) for SSC CGL Chemistry MCQ

Ernest Rutherford and his fellows Geiger and Marsden proved between 1911 and 1913 the existence of the atomic nucleus. This scattering experiment led to the development of the Rutherford model (planetary model) of the atom, and eventually to the Bohr model.

Answer is Option (3) for SSC CGL Chemistry MCQ

When a metal atom is strongly heated, its electrons absorb the heat energy and jump to a higher energy level. When the electron returns to its original position it gives off the energy it absorbed in the form of light. The result of all these jumps is to produce what is called an emission spectrum. An emission spectrum is a set of coloured lines that correspond to the energy the electron has released at each stage of its fall back to its original state.

Answer is Option (3) for SSC CGL Chemistry MCQ

In the Bhopal disaster which took place on 2-3 December, 1984 over 500,000 people were exposed to methyl isocyanate gas and other chemicals. The toxic substance made its way in and around the shantytowns located near the plant.

 Answer is Option (1) for SSC CGL Chemistry MCQ

Ammonium sulfate, (NH₄) ₂ SO₄ contains 21% nitrogen as ammonium cations, and 24% sulfur as sulfate anions. It is an inorganic salt which is most commonly used as a soil fertilizer.

Answer is Option (3) for SSC CGL Chemistry MCQ

A rectified alcohol is highly concentrated ethanol which has been purified by means of repeated distillation, a process that is called rectification. It typically contains 95% alcohol by volume and 5 % water. Normally, ethanol with 5 % water is known as pure alcohol.

Answer is Option (1) for SSC CGL Chemistry MCQ

Rust stains can be a challenge to remove because the stain consists of tiny iron oxide particles. Acidic solutions work best for these stains. The important ingredient in these removers is an acid – usually oxalic or hydrofluoric acid. The remover ingredients combine with the iron and loosen it from the fabric, then hold it in suspension in the wash water.

Answer is Option (3) for SSC CGL Chemistry MCQ

Mass of proton is 1.672621777(74) × 10^-27 kg. An electron has a mass 9.10938291(40) ×10^-31 kg that is approximately 1/1836 that of the proton. The mass of neutron is slightly larger than that of a proton. The mass of the hydrogen nucleus is 1.7 x 10^-27 kg. The heaviest of these particles is the neutron.

Answer is Option (2) for SSC CGL Chemistry MCQ

An emulsion is a mixture of two or more liquids that are normally immiscible (non-mixable or unblendable). Emulsions are part of a more general class of two-phase systems of matter called colloids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, milk, mayonnaise, and some cutting fluids for metal working.

Answer is Option (2) for SSC CGL Chemistry MCQ

The active ingredient in Dettol that confers its antiseptic property is chloroxylenol (C₈H₉ClO), an aromatic chemical compound. Chloroxylenol comprises 4.8% of Dettol’s total mixture, with the rest composed of pine oil, isopropanol, castor oil soap, caramel and water.

Answer is Option (4) for SSC CGL Chemistry MCQ

PNG is mainly methane – CH₄ with a small percentage of other higher hydrocarbons. The ratio of carbon to hydrogen is least in methane and hence it burns almost completely making it the cleanest fuel. Domestic PNG customers, also known as Residential customers, use gas for cooking purpose and also for heating water through gas geysers.

Answer is Option (1) for SSC CGL Chemistry MCQ

Ionization energy increases along a period with increase in atomic number. However, in the periodic table, going from left to right, while the Ionization Potential of Li is 5.4 eV, that of Be: 9.3 eV, B: 8.3 eV, C: 11.3 eV, N: 14.6 eV, O: 13.6 eV, and F: 17.0 eV.

Answer is Option (3) for SSC CGL Chemistry MCQ

The iron displaces copper from its salt, to make iron sulfate solution and deposit a thin coating of metallic copper on the surface of the metal. In general, any metal higher than copper in the “electromotive series” will displace copper from copper sulfate solution.

92. When Arsenic atoms are added to Germanium lattice, it becomes a/an

(1) Insulator

(2) Superconductor

(3) Intrinsic semiconductor

(4) Extrinsic semiconductor

Show Answer

Answer is Option (4) for SSC CGL Chemistry MCQ

When a pentavalent (donor) impurity, like arsenic, is added to germanium, it will form covalent bonds with the germanium atoms, leaving 1 electron relatively free in the crystal structure. Pure germanium may be converted into an N-type semiconductor by “doping” it with any donor impurity having 5 valence electrons in its outer shell. Semiconductors which are doped in this manner – either with N- or P-type impurities – are referred to as EXTRINSIC semiconductors.

 Answer is Option (3) for SSC CGL Chemistry MCQ

Helium is used to dilute the oxygen and nitrogen to reduce these affects. Helium is the gas of choice to use because it is an inert gas, is thinner, therefore more compressible than air, and its narcotic properties are negligible in comparison to nitrogen.

Answer is Option (4) for SSC CGL Chemistry MCQ

Fluorine cannot form oxyacid because fluorine is more electronegative than oxygen. For oxygen to bind, it must be a positively charged ion.

Answer is Option (3) for SSC CGL Chemistry MCQ

When the toxic effect of the mixture is greater than that expected for the sum of individual constituent doses, which is that effects of combined doses are more-than-additive, the interactions are said to be synergistic. Conversely, when the toxic effect of the mixture is less than that expected under the dose additivity assumption, the interactions are said to be antagonistic.

Answer is Option (1) for SSC CGL Chemistry MCQ

A trickling filter, also known as percolating filter, is an artificial bed of stone or broken brick material over which waste water or sewage is allowed to sprinkle or to trickle. It is then collected through the under drainage system.

97. Neutrons are slowed down in a nuclear reactor by

(1) Fissionable material

(2) Moderator

(3) Control rods

(4) Cooling system

Show Answer

Answer is Option (2) for SSC CGL Chemistry MCQ

In thermal nuclear reactors, the coolant acts as a moderator that must slow down the neutrons before they can be efficiently absorbed by the fuel. It allows neutrons to slow down to energies where they can easily cause a nucleus to fission.

Answer is Option (2) for SSC CGL Chemistry MCQ

Copper (Cu) has the atomic number of 29. Copper belongs to the d-block which is the collective name for Groups 3 to 12 in the periodic table. Most of the d-block elements are considered to be metals, with a common lustrous metallic appearance.

Answer is Option (2) for SSC CGL Chemistry MCQ

Sulfuric acid is used as a catalyst for refining and for producing alkylate, an essential component of highoctane fuel. The hydrocarbon molecules are reformed into more complex molecules with a higher octane rating value.

Answer is Option (1) for SSC CGL Chemistry MCQ

Synergy is the interaction of multiple elements in a system to produce an effect different from or greater than the sum of their individual effects. On the other hand, antagonism is the combined action of two or more substances to produce an effect less than the sum of their individual effects.