chemistry qus

1. What is the white precipitate formed when carbon dioxide is passed through lime water?

• a) Calcium hydroxide

• b) Calcium carbonate

• c) Sodium carbonate

• d) Zinc hydroxide

2. What gas is evolved when zinc reacts with sodium hydroxide?

• a) Oxygen

• b) Carbon dioxide

• c) Hydrogen

• d) Nitrogen

3. What is the chemical formula of sodium zincate?

• a) Na₂ZnO₂

• b) Na₂CO₃

• c) Zn(OH)₂

• d) ZnO

4. Why is granulated zinc used instead of powdered zinc in the reaction with sodium hydroxide?

• a) To increase the rate of reaction

• b) To slow down the reaction

• c) To prevent zinc from dissolving

• d) To change the color of the solution

5. What is the role of sodium hydroxide in the reaction with zinc?

• a) It acts as an oxidizing agent

• b) It reacts with zinc to form sodium zincate

• c) It releases carbon dioxide gas

• d) It acts as a neutralizing agent