CHAPTER 1 CHEMICAL REACTIONS AND EQUATIONS MCQ

Question 1 one of the following does not happen during a chemical reaction. This is

1. Breaking of old chemical bonds and formation of new chemical bonds
2. Formation of new substances with entirely different properties
3. Atoms of one element change into those of another element to form new products.
4. Rearrangement of atoms takes place to form new products.

Answer 1. 3. Atoms of one element change into those of another element to form new products.

Question 2. Which of the following does not involve a chemical reaction?

1. Digestion of food in our body
2. Process of respiration
3. Burning of candle wax when heated
4. Melting of candle wax on heating

Answer 2. 3. Melting of candle wax on heating.

Question 3. You are given the solution of lead nitrate. In order to obtain a yellow precipitate you should mix with it a solution of

1. Potassium chloride
2. Potassium nitride
3. Potassium sulphide
4. Potassium iodide

Answer 3. 4. Potassium iodide

Question 4. An acid which can decolourise purple coloured potassium permanganate solution is

1. Sulphuric acid
2. Citric acid
3. Carbonic acid
4. Hydrochloric acid

Answer4. 2. Citric acid

Question 5. The chemical reaction between two substances is characterized by a change in colour from Orange to green. These two substances are most likely to be

1. Potassium dichromate solution and Sulphur dioxide
2. Potassium permanganate solution and Sulphur dioxide
3. Potassium permanganate solution and lemon juice
4. Potassium dichromate solution and carbon dioxide

Answer 5. 1. Potassium dichromate solution and Sulphur dioxide.

Question 6. The chemical reaction between quicklime and water is characterized by

1. Evolution of hydrogen gas
2. Formation of slaked lime precipitate
3. Change in temperature of mixture
4. Change in colour of the product

Answer 6. 3. Change in temperature of mixture .

Question 7. One of the following is an endothermic reaction. This is

1. Combination of carbon and oxygen to form carbon monoxide
2. Combination of nitrogen and oxygen to form nitrogen monoxide
3. Combination of glucose and oxygen to form carbon dioxide and water.
4. Combination of zinc and hydrochloric acid to form zinc chloride and hydrogen

Answer 7. 2. Combination of nitrogen and oxygen to form nitrogen monoxide.

Question 8. Which of the following is not an endothermic reaction

1. CaCO3——— CaO + CO2
2. 2H2O——2H2 + O2
3. 6CO2 + 6H2O——C6H12O6 + 6O2
4. C6H12O6 + 6O2——-6CO2 + 6H2O

Answer 8. 4 C6H12O6 + 6O2——-6CO2 + 6H2O

Question 9. One of the following is an exothermic reaction. This is

1. Electrolysis of water
2. Conversion of limestone into quicklime
3. Process of respiration
4. Process of photosynthesis

Answer 9. 3. Process of respiration

Question 10. The chemical equation are balanced to satisfy one of the following laws in chemical reactions. This law is known as

1. Law of conservation of momentum
2. Law of conservation of mass
3. Law of conservation of motion
4. Law of conservation of magnetism

Answer 10. 2. Law of conservation of mass

Question 11. The removal of oxygen from a substance is called

1. Oxidation
2. Corrosion
3. Reduction
4. Rancidity

Answer 11. 3. Reduction

Question 12. In a context of redox reactions, the removal of hydrogen from a substance is known as

1. Oxidation
2. Dehydration
3. Reduction
4. Dehydrogenation

Answer 12. 1. Oxidation

Question 13.The chemical reaction involved in the corrosion of iron metal is that of

1. Oxidation as well as displacement
2. Reduction as well as combination
3. Oxidation as well as combination
4. Reduction as well as displacement

Answer 13. 3.Oxidation as well as combination.

Question 14. The term used of indicate the development of unpleasant smell and taste in fat and oil containing foods due to aerial oxidation is

1. Acidity
2. Radioactivity
3. Rabbity
4. Rancidity

Answer 14. 4. Rancidity

Question 15. In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of

1. Cl2
2. H2
3. N2
4. O2

Answer 15. 3. N2

Question 16. A white precipitate can be obtained by adding dilute sulphuric acid to

1. CuSO4 solution
2. NaCl solution
3. BaCl2 solution
4. Na2SO4 solution

Answer 16. 3. BaCl2 solution

Question 17. A white precipitate will be formed if we add common salt solution to

1. Ba(NO3)2 solution
2. KNO3 solution
3. AgNO3 solution
4. Mg(NO3)2 solution

Answer 17. 3.AgNO3 solution

Question 18. The process of respiration is

1. An oxidation reaction which is endothermic
2. A reduction reaction which is exothermic
3. A combination reaction which is endothermic
4. An Oxidation reaction which is exothermic

Answer 18. 4. An oxidation reaction which is exothermic.

Question 19. Which of the following can be decomposed by the action of light?

1. NaCl
2. KCl
3. AgCl
4. CuCl

Answer 19. 3. AgCl

Question 20. You are given the following chemical equation

Mg (s) + CuO(s)———- MgO(s) + Cu(s)

This equation represents

1. Decomposition reaction as well as displacement reaction
2. Combination reaction as well as double displacement reaction
3. Redox reaction as well as displacement reaction
4. Double displacement reaction as well as redox reaction

Answer 20. 3. Redox reaction as well as displacement reaction.

Question 21. Which of the following is a physical change

1. Formation of curd from milk
2. Ripening of fruits
3. Getting Salt from seawater
4. Burning of wood

Answer 21. 3 getting Salt from seawater

Reason- the changes, which can give back the reactants by physical means are called physical changes.