All Free Chemistry MCQs with Answers

• A. 8.314 atm dm3 mol K-1
• B. 0.0821 Jmol-1 K-1
• C. 62.4 torr cm3 mol-1K-1
• D. 8.314 x 10^7erg mol-1K-1

Explanation: R=8.3143 Nm.mol-1.K-1 1Nm=107erg Hence,8.3143*107erg.mol-1K-1

• A. 100 dm3
• B. 75 dm3
• C. 19.5 dm3
• D. 51 dm3

Explanation: To find the volume of the gas at STP (Standard Temperature and Pressure), we apply the combined gas law equation:(P1 * V1) / T1 = (P2 *…

• A. Roasted calcareous material
• B. Roasted gypsum
• C. Roasted argillaceous
• D. Roasted calcareous and argillaceous material

Explanation: Option D is the correct choice because it accurately describes the composition of clinker as a mixture of roasted calcareous and…

• A. Order of reaction helps us to determine mechanism of reaction
• B. Arrhenius equation is used to determine activation energy
• C. When a specific rate constant has a smaller value, then activation energy is smaller
• D. A type of catalysis in which reactant and catalyst are in the same phase is known as homogeneous catalysis

Explanation: This statement is incorrect. Activation energy is not directly related to the specific rate constant.

• A. Forms a colloidal solution with water
• B. Is insoluble in water
• C. Does not form an emulsion with the grease
• D. Forms an emulsion with the grease

Explanation: A soap molecule requires a long, non-polar hydrocarbon tail to effectively dissolve in and emulsify grease particles.

• A. Soaps and detergents both are used only in soft water
• B. Soaps and detergents both are used in soft as well as hard water
• C. Soap is used effectively only in soft water while detergent can be used in soft as well as hard water
• D. Detergent is used only in soft water, while soap is used in soft and hard water

Explanation: Soaps react with the calcium and magnesium ions in hard water to form an insoluble precipitate called scum.

• A. Disinfectant
• B. Chemosterilant
• C. Tranquillisers
• D. Plant growth hormones

Explanation: The combination of chloroxylenol and terpineol is the active formulation for the well-known antiseptic disinfectant Dettol.

• A. N2O4 + acrylic rubber
• B. N2O4 + UDMH
• C. Polybutadiene + ammonium perchlorate
• D. Nitroglycerine + nitrocellulose

Explanation: A liquid propellant system requires a liquid fuel and a liquid oxidizer.

• A. Azo dyes
• B. Phthalein dyes
• C. Anthraquinone dyes
• D. Triphenylmethane dyes

Explanation: Both malachite green and rosaniline are examples of triphenylmethane dyes.

• A. Sodium stearate
• B. Calcium stearate
• C. Sodium acetate
• D. Sodium benzoate

Explanation: An ordinary soap is the sodium or potassium salt of a longchain fatty acid.

• A. Both are fatty acids having the same number of carbon atoms
• B. Both are saturated fatty acids
• C. One olefinic bond is present in oleic acid
• D. The alkyl group of stearic acid contains 35 hydrogen atoms

Explanation: Stearic acid is a saturated fatty acid (with no C=C double bonds). Oleic acid is a monounsaturated fatty acid, meaning it contains one C=C…

• A. It is a drying oil
• B. It is used in paints and varnishes
• C. It is a vegetable oil
• D. It is a triglyceride of saturated fatty acids

Explanation: Linseed oil is classified as a "drying oil" because it is rich in polyunsaturated fatty acids (like linolenic acid).

• A. The aliphatic polyamides are generally known as Nylons
• B. The aliphatic polyamides are generally known as polyesters
• C. The aliphatic polyamides are generally known as rayons
• D. None of the above

Explanation: "Nylon" is the generic designation for a family of synthetic polymers composed of polyamides (repeating units linked by amide bonds).

• A. Plastic
• B. Petroleum
• C. Starch
• D. Natural rubber

Explanation: A polymer is a macromolecule made of repeating monomer units. Petroleum (crude oil) is a complex mixture of many different hydrocarbon…

• A. Nylon-6,6
• B. Polyethylene
• C. Dacron (polyester)
• D. Bakelite

Explanation: Polyethylene is formed by the addition polymerization of ethylene monomers (C₂H₄).

• A. Natural rubber is a hydrocarbon
• B. Natural rubber is isoprene
• C. Natural rubber is a polymer of 1,3-Butadiene
• D. Natural rubber can be vulcanized

Explanation: The correct answer is Option A: 'Natural rubber is a hydrocarbon'. Natural rubber is composed of polyisoprene, which is a hydrocarbon.

• A. Organic waste into drinking water
• B. Oil spill in water
• C. Industrial waste mercury into fishing water
• D. Aresenic into the atmosphere

Explanation: Minamata disease is severe mercury poisoning disease that is caused due to release of industrial waste mercury into fishing water.

• A. Both are fatty acids having same number of carbon atoms
• B. Both are saturated fatty acids
• C. One olefinic bond is present in oleic acid
• D. The alkyl group of stearic acid contains 35 hydrogen atoms

Explanation: Stearic acid is saturated and oleic acid is unsaturated fatty acid. Their structure are:

• A. Wool wax
• B. Carnauba wax
• C. Beeswax
• D. Spermaceti was

Explanation: Carnauba wax is a natural wax obtained from the leaves of the Copernicia prunifera palm plant.

• A. Antipyratics
• B. Tranquilizers
• C. Analgesics
• D. None of above

Explanation: Tranquilizers are designed to treat anxiety, fear, tension etc by inducing sleep through central nervous system.