Answer is Option (3) for SSC CGL Chemistry MCQ

Inspirable copper dust takes a predominantly fibrous effect. The ALV of copper aerosol in the workplace atmosphere is 0.5 mg/m³, while the threshold limit value (TLV) is 1.0 mg/m³.

Answer is Option (3) for SSC CGL Chemistry MCQ

In order to manufacture silicones, alkyl-substituted chlorosilanes are used as starting material. Since dimethylsilane contains —OH group at the end of the chain, polymerization and chain length increases. However, the hydrolysis of alkyl trichlorosilane gives very complex cross linked polymer.

Answer is Option (4) for SSC CGL Chemistry MCQ

Examples of natural colloids can be found in our body itself: blood consists of colloidal sized red blood corpuscles (RBC) which provide the vital oxygen to all the body tissues.

Answer is Option (3) for SSC CGL Chemistry MCQ

Nickel silver, also known as German silver, 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.

Answer is Option (2) for SSC CGL Chemistry MCQ

Atomic absorption spectroscopy is an analytical chemistry technique used for determining concentration of particular metal element and is widely used in pharmaceutics. It was used for the determination of cobalt in Vitamin B₁₂.

Answer is Option (1) for SSC CGL Chemistry MCQ

Containment of toxic or hazardous constituents in industrial solid wastes is currently being accomplished using:

(i) coating grains of waste material with an inert and non-reactive impervious material (microencapsulation), and

(ii) coating blocks of waste material with an inert, non-reactive impervious material (macroencapsulation).

Answer is Option (4) for SSC CGL Chemistry MCQ

UV radiation can be an effective viricide and bactericide. Disinfection using UV radiation is commonly used in wastewater treatment applications and is finding an increased usage in drinking water treatment.

Answer is Option (4) for SSC CGL Chemistry MCQ

Cast Iron is a hard, brittle, nonmalleable iron carbon alloy, cast into shape. It contains 2 to 4.5 percent carbon, 0.5 to 3 percent silicon, and lesser amounts of sulfur, manganese, and phosphorus.

Answer is Option (4) for SSC CGL Chemistry MCQ

Octane rating or octane number is a standard measure of the performance of a motor or aviation fuel. The higher the octane number, the more compression the fuel can withstand. Isooctane (upper) has an octane rating of 100 whereas n-heptane has an octane rating of 0.

Answer is Option (2) for SSC CGL Chemistry MCQ

Nitrous oxide is one of the more well-known anesthetic gases, and has been in use for around 200 years. Unlike some other anesthetics, this compound can be used both for inducing unconsciousness and pain control. Chloroform is more potent and more toxic than ether. Its use as an anaesthetic decreased with increased experience and knowledge of its dangers.

Answer is Option (3) for SSC CGL Chemistry MCQ

The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic. The pH scale is logarithmic and as a result, each whole pH value below 7 is ten times more acidic than the next higher value.

Answer is Option (2) for SSC CGL Chemistry MCQ

Water is the enabler of fast oxidation of iron. So freshwater will also cause rust. However, salt water (sea water) is a very good conductor (lots of dissociated ions) and so there are a number of electrolysis reactions that tremendously accelerate corrosion in salt water. This effect can be reversed by using a metal (like zinc) which causes the current to be reversed and in effect the zinc corrodes rapidly, protecting the iron.

Answer is Option (4) for SSC CGL Chemistry MCQ

Aerated water is, correctly speaking, water to which air is added. So aerated water is any water artificially impregnated with a large amount of gas (as carbon dioxide). The term is, however, frequently applied to carbonated water.

Answer is Option (2) for SSC CGL Chemistry MCQ

Magnetite is a mineral, one of the two common naturally occurring iron oxides (chemical formula Fe₃O₄). It is the most magnetic of all the naturally occurring minerals on Earth. The chemical IUPAC name of magnetite is iron oxide and the common chemical name is ferrous-ferric oxide.

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

When cathode rays strike a solid target of high atomic weight and high melting point such as tungsten, molybdenum, etc, they give rise to a highly penetrating radiation called the X-rays.

Answer is Option (1) for SSC CGL Chemistry MCQ

The major use of sulphur is in the manufacture of sulphuric acid (H₂SO₄) which is one of the most important compounds made by the chemical industry. It is used to make, literally, hundreds of compounds needed by almost every industry.

Answer is Option (3) for SSC CGL Chemistry MCQ

Each element’s atoms have a different number of protons, neutrons, and electrons, which is why they have different atomic numbers, difference in valence electrons and other properties. Their reactivity also varies because of the number and activeness of the electrons in the atom.

Answer is Option (1) for SSC CGL Chemistry MCQ

Organic compounds are always covalent compounds because it is more energetically favorable for carbon to covalently bond. Organic compounds, such as carbohydrates, lipids, proteins and nucleic acids, are all examples of covalent compounds.

Answer is Option (2) for SSC CGL Chemistry MCQ

Alkali metals such as Lithium are the most electropositive elements in the periodic table. As alkali metals have low ionization energies, they have a great tendency to lose electrons forming uni-positive ions.

Answer is Option (2) for SSC CGL Chemistry MCQ

Zinc phosphide is an inorganic compound that is used in pesticide products as a rodenticide. Formulated as attractive bait, it releases phosphine gas once it is exposed to acid and moisture in the stomach. The phosphine gas is very toxic to all animals.

Answer is Option (2) for SSC CGL Chemistry MCQ

An antacid is a base which neutralizes stomach acidity. The most common of these bases are hydroxides, carbonates, or bicarbonates such as Aluminum hydroxide, Calcium carbonate, Magnesium carbonate, Magnesium hydroxide, and Sodium bicarbonate.

Answer is Option (2) for SSC CGL Chemistry MCQ

Nitrogen, required in large quantities for healthy plant growth, is supplied either as a cation (ammonium – NH₄₊ ) or an anion (nitrate – NO_3– ). The ratio of these two forms of nitrogen in the nutrient solution can have large effects on both the rate and direction of pH changes with time.

Answer is Option (2) for SSC CGL Chemistry MCQ

In quantum chromodynamics, nucleons are regarded as composites of three quarks (elementary particles) and pions are composites of two quarks. According to EOB’s rules, nucleons move as fermions while pions move as bosons.

Answer is Option (2) for SSC CGL Chemistry MCQ

Greenhouse gases are those that can absorb and emit infrared radiation, but not radiation in or near the visible spectrum. The most abundant greenhouse gases in Earth’s atmosphere are: Water vapor (H₂O), Carbon dioxide (CO₂), Methane (CH₄), Nitrous oxide (N₂O), Ozone (O₃) and CFCs.

Answer is Option (2) for SSC CGL Chemistry MCQ

Injury caused by sulphur oxides show interveinal necrotic areas that are light tan to white. Uninjured tissue next to the veins remains green.

Answer is Option (4) for SSC CGL Chemistry MCQ

Chlorofluorocarbons (CFCs) have been held responsible for the depletion of ozone layer. The manufacture of CFCs has been phased out under the Montreal Protocol, and they are being replaced with other products such as HFCs.

Answer is Option (4) for SSC CGL Chemistry MCQ

Caffeine (C₈H₁₀N₄O₂) is a bitter alkaloid found especially in coffee, tea, cacao, and kola nuts. It is used medicinally as a stimulant and diuretic.

Answer is Option (3) for SSC CGL Chemistry MCQ

Nickel-based super alloys are an unusual class of metallic materials with an exceptional combination of high temperature strength, toughness, and resistance to degradation in corrosive or oxidizing environment. These materials are widely used in aircraft and power-generation turbines, rocket engines, etc.

Answer is Option (1) for SSC CGL Chemistry MCQ

Vulcanization is a chemical process for converting natural rubber into more durable materials via the addition of sulfur or other equivalent curatives or accelerators. These additives modify the polymer by forming cross-links (bridges) between individual polymer chains.

Answer is Option (1) for SSC CGL Chemistry MCQ

The noble gases are the chemical elements in group 18 of the periodic table. This chemical series contains helium, neon, argon, krypton, xenon, and radon.

Answer is Option (1) for SSC CGL Chemistry MCQ

Sodium is a very reactive metal. It reacts vigorously with oxygen and water. A lot of heat is generated in this process. Therefore, it is stored in kerosene to avoid contacts between either atmospheric oxygen or water.

Answer is Option (1) for SSC CGL Chemistry MCQ

The atomic radius is the distance from the atomic nucleus to the outermost stable electron orbital in an atom that is at equilibrium. It tends to decrease across a period from left to right. It usually increases while going down a group due to the addition of a new energy level (shell).

Answer is Option (2) for SSC CGL Chemistry MCQ

A vulcanized flexible tyre rubber contains about 3 –5% of sulphur whereas hard rubber (ebonite) contains about 32% of sulphur. The stiffness of vulcanized rubber depends on the amount of sulphur added.

Answer is Option (4) for SSC CGL Chemistry MCQ

Galena is the most abundant lead mineral. It is a metallic, lead-gray mineral with cubic cleavage and a distinctly high density. It belongs to the octahedral sulfide group of minerals with metal ions in octahedral positions.

Answer is Option (3) for SSC CGL Chemistry MCQ

Light water (ordinary water) is used as the moderator in U.S. reactors as well as the cooling agent. It acts as the means by which heat is removed to produce steam for turning the turbines of the electric generators.

37. The chemical name of “Plaster of Paris” commonly used for setting broken bones is

(1) Calcium nitrate

(2) Calcium sulphate

(3) Calcium carbonate

(4) Calcium chloride

Show Answer

Answer is Option (2) for SSC CGL Chemistry MCQ

Plaster of Paris is the common name of Calcium Sulphate hemihydrate, with chemical formula: CaSO₄. 1/2H₂O. Plaster of Paris is produced by heating gypsum to about 150°C.

Answer is Option (1) for SSC CGL Chemistry MCQ

A pH meter is an electronic device used for measuring the pH (acidity or alkalinity) of a liquid. A typical pH meter consists of a special measuring probe (a glass electrode) connected to an electronic meter that measures and displays the pH reading.

Answer is Option (4) for SSC CGL Chemistry MCQ

Natural and wastewater contain small particulates that are suspended in water forming a colloid. These particles carry the same charges, and repulsion prevents them from combining into larger particulates to settle. Historically, dirty water is cleaned by treating with alum, Al₂ (SO₄)₃ .12 H₂O, and lime, Ca(OH)₂ . The phenomenon is known as coagulation:

Al ₂ (SO₄)₃ .12 H₂O Al(aq)³⁺ + 3SO₄ (aq)^2- + 12H₂O

SO4 (aq)^2- + H₂O HSO₄ (aq)^– + OH^– (causing pH change)

Ca(OH)₂ Ca(aq)²⁺ + 2 OH^– (causing pH change)

The slightly basic water causes Al(OH)₃ , Fe(OH)₃ and Fe(OH)₂ to precipitate, bringing the small particulates with them and the water becomes clear.

Answer is Option (1) for SSC CGL Chemistry MCQ

Brass is an alloy made of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties. By comparison, bronze is principally an alloy of copper and tin.

Answer is Option (4) for SSC CGL Chemistry MCQ

Wrought iron or malleable iron is the purest form of commercial iron as it contains the lowest percentage of carbon (0.12-0.25%) and impurities of S, P, Mn and Si in minute amount (about 0.3%). It is made by melting cast iron with scrap iron in a reverberatory furnace lined with Fe₂O₃ which oxidizes C, Si, P, etc, most of which are then removed by rolling.

Answer is Option (2) for SSC CGL Chemistry MCQ

Galvanization is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanization, in which parts are submerged in a bath of molten zinc.

Answer is Option (2) for SSC CGL Chemistry MCQ

In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent. The solution more or less takes on the characteristics of the solvent including its phase.

Answer is Option (2) for SSC CGL Chemistry MCQ

Photochemical smog which is mainly composed of ozone (O₃), Peroxyacetyl nitrate (PAN) and Nox , is also known as brown air where solar radiation is intense. In seasons of lesser solar radiation or areas, smog formation is incomplete and the air is referred to as grey air.

Answer is Option (2) for SSC CGL Chemistry MCQ

When solid Potassium Permanganate (KMnO₄) is mixed with pure glycerol or other simple alcohols, it will result in a violent combustion reaction. Potassium Permanganate is an extremely powerful oxidizer which spontaneously ignites after coming in contact with glycerol. The glycerol is oxidized so quickly that heat is generated faster than it can be dissipated.

3 C₃H₅ (OH)₃ + 14 KMnO₄ → 14 MnO₂ + 7 K₂CO₃ + 2 CO₂ + 12 H₂O

Answer is Option (4) for SSC CGL Chemistry MCQ

Chlorine is used to disinfect water and is part of the sanitation process for sewage and industrial waste. During the production of paper and cloth, it is used as a bleaching agent. It is also used in cleaning products; including household bleach which is chlorine dissolved in water Bleaching powder is an important and a commonly used bleaching agent prepared from chlorine.

Answer is Option (3) for SSC CGL Chemistry MCQ

Recent research has shown that India’s groundwater faces the problem of presence of uranium, arsenic, and heavy metals in ground water used for drinking. Sorbitol (used as artificial sweetener) and Formaldehyde (used in coating, etc) are not famous as water pollutants.

Answer is Option (4) for SSC CGL Chemistry MCQ

Cyanide poisoning occurs on exposure to a compound that produces cyanide ions when dissolved in water. The cyanide ion halts cellular respiration by inhibiting an enzyme in the mitochondria called cytochrome coxidase. If cyanide is inhaled it causes a coma with seizures, apnea, and cardiac arrest, with death following in a matter of seconds.

Answer is Option (2) for SSC CGL Chemistry MCQ

Bauxite, an aluminium ore, is the world’s main source of aluminium. Bauxite is primarily comprised of aluminum oxide compounds (alumina), silica, iron oxides and titanium dioxide. It is refined through the Bayer chemical process into alumina. Alumina is refined into pure aluminum metal through the Hall– Héroult electrolytic process.

Answer is Option (2) for SSC CGL Chemistry MCQ

Arsenic, beryllium, cadmium, chromium, lead, manganese, mercury, nickel, and selenium are some of the metals called ‘heavy’ because of their high relative atomic mass. They persist in nature and can cause damage or death in animals, humans, and plants even at very low concentrations.

Answer is Option (4) for SSC CGL Chemistry MCQ

Photochemical smog is a unique type of air pollution which is caused by reactions between sunlight and pollutants like hydrocarbons and nitrogen dioxide (NO and NO₂). Other components of the photochemical smog include Ozone (O₃) formaldehyde, peroxy benzoyl nitrate (PBzN), peroxy acetyl nitrate (PAN) and acrolein. The formation of photochemical smog can be expressed in the simple terms as:

Hydrocarbons + NO_x + sunlight

Answer is Option (1) for SSC CGL Chemistry MCQ

In 1905, it was Einstein who suggested the concept of light having a dual nature; particle and wave nature. In a similar way, Louise de Broglie suggested that electron also exhibits a dual nature. Broglie derived a mathematical expression to prove the wave nature of electron along with particle nature. He gave the following relation:-  ë =h/mí, where ë -is the wavelength of electron, m – is mass of an electron and í – is the frequency.

Answer is Option (2) for SSC CGL Chemistry MCQ

When metals are required in a ultra pure state, the zone refining method is used. The principle-employed states that the impurities, which lower the melting point of a metal remain preferentially dissolved in the liquid phase and purer metal will emerge in the solid phase.

Answer is Option (2) for SSC CGL Chemistry MCQ

In 1967, based on Einstein defining the speed of light as the most constant dimension in the universe, the International System of Units isolated two specific wave counts from an emission spectrum of caesium-133 to co-define the second and the meter. Since then, caesium has been widely used in highly accrate atomic clocks. Among alkali metals, cesium has lowest ionization energy and hence it can show photo electric effect to the maximum extent.

Answer is Option (3) for SSC CGL Chemistry MCQ

Transition metals are used directly as catalysts in the anti–pollution catalytic converters in car exhausts. For example, expensive transition metals such as Platinum and rhodium are used in the catalytic converters in car exhausts to reduce the emission of carbon monoxide and nitrogen monoxide, which are converted to the non–polluting gases nitrogen and carbon dioxide.

2NO (g) + 2CO(g) ⇒ N2 (g) + 2CO₂ (g)

Answer is Option (3) for SSC CGL Chemistry MCQ

The red, orange, yellow, green, blue and purple colors exploding in the night sky during a pyrotechnic festival are created by the use of metal salts. Barium chloride provides green colour to firework displays. Metal salts that are commonly used in firework displays include: strontium carbonate (red), calcium chloride (orange), sodium nitrate (yellow), barium chloride (green fireworks) and copper chloride (blue fireworks).

Answer is Option (4) for SSC CGL Chemistry MCQ

The ability of radioactivity to pass through materials is called its penetrating ability. Penetrating ability depends on the size of the radioactive particle. Alpha particles are the biggest, beta particles are very much smaller and gamma rays have no mass. Ultraviolet rays have less energetic photons compared to gamma rays and x-rays and a lower penetration power. Gamma rays are the most penetrating of the radiations.

Answer is Option (3) for SSC CGL Chemistry MCQ

German Silver (also known as New Silver, Nickel Brass, etc) is a copper alloy with nickel and often zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. It is named for its silvery appearance, but it contains no elemental silver unless plated.

Answer is Option (1) for SSC CGL Chemistry MCQ

Nitrous oxide (N₂O) and methane (CH₄) are the two major greenhouse gasses (GHG) emitted by agricultural activities. N₂O accounts for around 8% of the warming impact of current human GHG emissions. Agricultural activities that directly increase N₂O emissions are: fertilization, application of manure or other organic materials, retention of crop residues, production of nitrogen-fixing crops and forages, and cultivation of soils with high organic matter content. Irrigation, drainage, tillage practices and fallowing of land also increase N₂O emission.

Answer is Option (2) for SSC CGL Chemistry MCQ

Acid rain is caused by emissions of Sulfur Dioxide (SO₂) and Nitrogen Oxide (NO), which react with the water molecules in the atmosphere to produce acids. Emissions of SO₂ and NO result from fossil fuel combustion. The chemicals in acid rain can cause paint to peel, corrosion of steel structures such as bridges, and erosion of stone statues.

Answer is Option (1) for SSC CGL Chemistry MCQ

Chlorofluorocarbon contributes to ozone depletion in the upper atmosphere. It is an organic compound that contains only carbon, chlorine, and fluorine, produced as a volatile derivative of methane, ethane, and propane. Its manufacture has been phased out under the Montreal Protocol.

Answer is Option (3) for SSC CGL Chemistry MCQ

The most abundant metal on Earth is aluminum. Aluminum is the third most abundant element in the Earth’s crust, and makes up 8 percent of it by parts per million. The most abundant element in the Earth’s crust is Oxygen followed by Silicon. Both of these are non-metals.

Answer is Option (4) for SSC CGL Chemistry MCQ

Deep-sea divers have their oxygen supply mixed with helium in order to avoid the toxic nature of oxygen under extreme pressures. The Helium atom is much smaller than the Nitrogen molecule, has a smaller electron cloud and is less polarizable. It, therefore, is less soluble in blood than nitrogen and prevents the formation of nitrogen bubbles in blood which blocks blood flow as the diver comes to the surface of the sea from underwater.

Answer is Option (4) for SSC CGL Chemistry MCQ

Terylene is a co-polymer of ethylene glycol and Terephthalic acid. Also known as Dacron, it is prepared by the condensation polymerization of ethylene glycerol and Terephthalic acid with elimination of water. The reaction is carried out at about 420-460 K in the presence of a catalyst consisting of a mixture of zinc acetate and antimony trioxide.

Answer is Option (2) for SSC CGL Chemistry MCQ

Acid rain is caused by emissions of sulfur dioxide (SO₂) and nitrogen oxide (NO_X), which react with the water molecules in the atmosphere to produce acids. The SO₂ and NO_X react with water, oxygen and other chemicals to form sulfuric and nitric acids. The chemicals in acid rain can cause paint to peel, corrosion of steel structures and weathering of stone buildings.

Answer is Option (1) for SSC CGL Chemistry MCQ

Zeolites are hydrated aluminosilicate minerals made from interlinked tetrahedra of alumina (AlO₄ ) and silica (SiO₄). In simpler words, they’re solids with a relatively open, three-dimensional crystal structure built from the elements aluminium, oxygen, and silicon, with alkali or alkaline-Earth metals (such as sodium, potassium, and magnesium) plus water molecules trapped in the gaps between them.

Answer is Option (3) for SSC CGL Chemistry MCQ

Liquefied petroleum gas or liquid petroleum gas (LPG) is mostly propane (C₃H₈ ), or butane (C₄H₁₀). They are most commonly mixtures of these two hydrocarbon gases that are used as fuel in heating appliances, cooking equipment, and vehicles. In the northern hemisphere winter, the mixes contain more propane, while in summer, they contain more butane.

Answer is Option (3) for SSC CGL Chemistry MCQ

The electrodes of the cells in a storage battery consist of lead grids. The openings of the anodic grid is filled with spongy (porous) lead. The openings of the cathodic grid is filled with lead dioxide (PbO₂). Dilute sulfuric acid (H₂ SO₄ ) serves as the electrolyte. Lead acid batteries, also known as lead storage batteries, can store a lot of charge and provide high current for short periods of time.

Answer is Option (4) for SSC CGL Chemistry MCQ

Biogas is essentially a mixture of Methane (CH₄ , around 55-75%) but also contains Carbon Dioxide (CO₂), around 25-30%), varying quantities of Water (H₂O) and Hydrogen Sulphide (H₂S). Other compounds can also be found, especially in waste dump biogas: Ammonia (NH₃), Hydrogen (H₂), Nitrogen (N₂) and Carbon Monoxide (CO). Methane is the valuable component under the aspect of using biogas fuel.

Answer is Option (3) for SSC CGL Chemistry MCQ

Iron is alloyed with carbon lo make steel and has the effect of increasing the hardness and strength of iron. Pure iron cannot be hardened or strengthened by heat treatment but the addition of carbon enables a wide range of hardness and strength. High-carbon stainless steel contains a minimum of 0.3% carbon. The higher the carbon content, the less formable and the tougher the steel becomes.

Answer is Option (2) for SSC CGL Chemistry MCQ

Lead sulfate (PbSO₄ ) is a white crystalline solid. It is insoluble in water and sinks in it. It is often seen in the plates/electrodes of car batteries, as it is formed when the battery is discharged. It is also known as fast white, milk white, sulfuric acid lead salt or anglesite.

Answer is Option (3) for SSC CGL Chemistry MCQ          

Heating wood to a very high temperature in the absence of air makes charcoal. When it is heated to an even higher temperature, about 930°C, impurities are driven from its surface and it becomes activated charcoal, sometimes called decolorizing charcoal. This activated charcoal can remove impurities in either the gaseous or liquid state from many solutions. It does so by the process of adsorption, or by attracting these molecules to the surface.

Answer is Option (4) for SSC CGL Chemistry MCQ

The Chernobyl disaster was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in the city of Pripyat, then located in the Ukrainian USSR. An explosion and fire released large quantities of radioactive particles into the atmosphere, which spread over much of the western USSR and Europe.

Answer is Option (3) for SSC CGL Chemistry MCQ

Thorium-rich monazite sand deposits on the Kerala coast has been responsible for natural radioactive contamination. It has been pronounced on the southwest coastal line of the state. The region has been found to have elevated levels of background radioactivity due to high abundance of thorium.

Answer is Option (3) for SSC CGL Chemistry MCQ

Fire extinguishers use carbon dioxide to displace the oxygen necessary for a fire to burn, extinguishing the blaze. Fires need oxygen, fuel, and heat to ignite, and removing any one of those three components can put out a fire. It is useful for electrical fires and some flammable liquid fires, but may make some gasoline or paper fires worse by dispersing burning material.

Answer is Option (4) for SSC CGL Chemistry MCQ

Quartz is a compound of one part silicon and two parts of oxygen, silicon dioxide, SiO₂ . Quartz is the most abundant silica mineral. It is used in a number of industries, the important being glass, foundry, sodium silicate, silicon alloys, etc. The various grades of sodium silicate are characterized by their SiO₂ : Na₂O weight ratio.

Answer is Option (3) for SSC CGL Chemistry MCQ

Chlorofluorocarbons (CFCs), also known as Freon, cause the breakdown of the ozone layer that protects the earth from the sun’s ultraviolet (UV) radiation. In the upper atmosphere, the UV-induced breakdown of CFCs releases free, highly reactive chlorine and bromine atoms that lead to the breakdown of the stratospheric ozone layer. Owing to ozone depletion in the upper atmosphere, CFCs have been phased out under the Montreal Protocol of 1987.

Answer is Option (2) for SSC CGL Chemistry MCQ

The allotropic form of Phosphorus (white phosphorus) is less stable and therefore highly reactive because of angular strain in P₄ molecule where the angles are only 60⁰ . Having very low ignition temperature, it readily catches fire in air to give dense white fumes of P₄O₁₀. So it is kept in water to avoid oxidation by the oxygen present in air.

Answer is Option (3) for SSC CGL Chemistry MCQ

Seawater is salty because rainwater dissolves the salt minerals found in soil and rocks as it travels through rivers and streams en route to the sea The rain that falls on the land contains some dissolved carbon dioxide from the surrounding air. This causes the rainwater to be slightly acidic due to carbonic acid. The rain physically erodes the rock and the acids chemically break down the rocks and carries salts and minerals along in a dissolved state as ions. The ions in the runoff are carried to the streams and rivers and then to the ocean which makes them Salty.

Answer is Option (2) for SSC CGL Chemistry MCQ

Even after the sunset when the sun goes down, the incoming radiation from the sun stops, but there is still a lot of radiation that has been absorbed by the earth, which is re-radiated in form of terrestrial radiation. Energy leaving the earth’s surface i.e. terrestrial radiation heats up the atmosphere more than the incoming solar radiation i.e. insolation.

Answer is Option (4) for SSC CGL Chemistry MCQ

Trinitrotoluene (C₆H₂ (NO₂) ₃CH₃), abbreviated as TNT, is sometimes used as a reagent in chemical synthesis, but it is best known as an explosive material with convenient handling properties. The explosive yield of TNT is considered to be the standard measure of bombs and other explosives.

Answer is Option (3) for SSC CGL Chemistry MCQ

Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The transformation of ammonia to nitrite is usually the rate limiting step of nitrification. Nitrification is an important step in the nitrogen cycle in soil.

 Answer is Option (3) for SSC CGL Chemistry MCQ

Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. The oxidation of ammonia into nitrite is performed by two groups of organisms, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Nitrification is an important step in the nitrogen cycle in soil.

Answer is Option (1) for SSC CGL Chemistry MCQ

Rainwater is often considered the purest form of water available on the Earth. The evaporation of water by the sun allows the salts and other impurities to be left behind out of the water. However, in reality, rain water is often much less than pure when it reaches the surface of the Earth due to the high pollution of air with toxic gases.

Answer is Option (2) for SSC CGL Chemistry MCQ

Fossil fuels — coal, petroleum, and natural gas — are the primary culprit behind climate change. They contribute more than 80 percent of greenhouse gas emissions — and 98 percent of CO₂ emissions alone. On the contrary, Geothermal energy is thermal energy generated and stored in the Earth. It is clean and sustainable.

Answer is Option (4) for SSC CGL Chemistry MCQ

Aluminium is an acceptor atom, an impurity atom in a semiconductor, which can accept or take up one or more electrons from the crystal and become negatively charged. In semiconductor physics. It is a dopant atom that when added to a semiconductor can form a p-type region. For example, when silicon (Si), having four valence electrons, needs to be doped as a p-type semiconductor, elements from group III like boron (B) or aluminium (Al), having three valence electrons, can be used. The latter elements are also called trivalent impurities. Other trivalent dopants include indium (In) and gallium (Ga).

Answer is Option (1) for SSC CGL Chemistry MCQ

The greenhouse gases in Earth’s atmosphere are: Watervapour (H₂O), Carbon dioxide (CO₂), Methane (CH₄), Nitrous oxide (N₂O), Ozone (O₃) and Chlorofluorocarbons (CFCs). Methane is an important greenhouse gas with a global warming potential of 34 compared to CO₂ over a 100-year period, and 72 over a 20-year period.

Answer is Option (4) for SSC CGL Chemistry MCQ

Energy is broadly classified as commercial and non-commercial energy. Firewood, agricultural waste (straw, etc.) and animals waste (cowdung) are the important components of non-commercial energy. Coal, petroleum products, natural gas and, electricity are the important components of commercial energy. These goods are largely used for commercial purposes in the factories and farms.

Answer is Option (4) for SSC CGL Chemistry MCQ

Cotton, starch, cellulose and rubber are some of the naturally occurring polymers. Starch is a condensation polymer made up of hundreds of glucose monomers, which split out water molecules as they chemically combine. Starch is a member of the basic food group carbohydrates and is found in cereal grains and potatoes. It is also referred to as a polysaccharide, because it is a polymer of the monosaccharide glucose.

Answer is Option (2) for SSC CGL Chemistry MCQ

Sulphur is a non-metal that shows allotropy in the liquid state. If sulphur is heated slowly the changes between the different forms can be observed. These changes are in the form of colour and viscosity (thickness) of the liquid. If the dark brown liquid sulphur is poured into a beaker of cold water, plastic sulphur is formed. This is an elastic, rubber-like form of sulphur.

Answer is Option (4) for SSC CGL Chemistry MCQ

Superphosphate is a common synthetic phosphorus fertilizer. It contains phosphorus and sulphur in a ratio of 1 to 1.22.?It is produced by treatment of “phosphate rock” with acids such as sulphuric acid. Superphosphate is the principal carrier of phosphate, the form of phosphorus usable by plants, and is one of the world’s most important fertilizers.

Answer is Option (3) for SSC CGL Chemistry MCQ

A thermal power station is a power plant in which heat energy is converted to electric power. Thermal power is producing using fossil fuel such as coal, natural gas or petroleum. More than 65% of India’s electricity generation capacity comes from thermal power plants, with about 85% of the country’s thermal power generation being coal-based.

 Answer is Option (2) for SSC CGL Chemistry MCQ

When iron rusts, oxide compounds are formed due the interaction between oxygen in the air or in water and the metal. Because of the oxygen atoms binding with the metal, the weight of the metal with rust will increase.

Answer is Option (2) for SSC CGL Chemistry MCQ

Silver is a fairly stable metal and under normal circumstances does not corrode quickly. However, it is particularly susceptible to the effects of the sulfide radical. However, when exposed to air, silver reacts with Hydrogen Sulphide in the atmosphere, especially in marine environment, and readily forms a surface tarnish of silver sulphide.

2Ag + H₂ S → Ag₂ S +H₂

Answer is Option (2) for SSC CGL Chemistry MCQ

Uranium (U) is a naturally occurring radioactive element. Its nucleus is unstable, so the element is in a constant state of decay, seeking a more stable arrangement. One of its isotopes, uranium-235, is the only naturally occurring isotope capable of sustaining a nuclear fission reaction. In fact, uranium was the element that made the discovery of radioactivity possible.

Answer is Option (2) for SSC CGL Chemistry MCQ

Bio-fertilizers are micro-organisms which bring about nutrient enrichment of soil by enhancing the availability of nutrients to crops. The micro-organisms which act as bio-fertilizers are bacteria, cyanobacteria (blue green algae) and mycorrhizal fungi. The symbiotic nitrogen-fixing bacteria convert free nitrogen to ammonia, which the host plant utilizes for its development.

Answer is Option (3) for SSC CGL Chemistry MCQ

Isotopes are forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei. So they have the same atomic number, but differ in relative atomic mass. For example, carbon-12, carbon-13 and carbon-14 are three isotopes of the element carbon having the same atomic number of 6, but with mass numbers 12, 13 and 14 respectively.

Answer is Option (1) for SSC CGL Chemistry MCQ

Concentrated nitric acid is a very strong oxidator capable of reacting with the noble metals such as copper or silver. Some precious metals, such as pure gold and platinum-group metals do not react with nitric acid. However, pure gold does react with aqua regia, a mixture of concentrated nitric acid and hydrochloric acid.

Answer is Option (1) for SSC CGL Chemistry MCQ

When sodium bicarbonate is strongly heated, it decomposes into sodium carbonate, water vapor, and carbon dioxide. Solid sodium carbonate is a white powder and is used in cooking under the name ‘baking powder’; sodium bicarbonate is used in baking under the name ‘baking soda’.

 2NaHCO_{3 (s)} → Na₂CO_{3 (s)} + CO_{2 (g)} + H₂O_(g)

Answer is Option (4) for SSC CGL Chemistry MCQ

Vinegar is mostly dilute acetic acid, often produced by fermentation and subsequent oxidation of ethanol. It is roughly 3–9% acetic acid by volume, making acetic acid the main component of vinegar apart from water.