Balancing a chemical equation is based on:

1. Law of conservation of mass
2. Mass of reactants and products
3. Symbols and formulae
4. None of the above

Copper carbonate when heated turns:

1. Blue
2. Green
3. Black
4. Yellow

When lead acetate solution is added to potassium iodide solution a precipitate is formed which is:

1. Red
2. Yellow
3. White
4. Black

When sodium carbonate reacts with dilute hydrochloric acid, the gas evolved is:

1. Carbon dioxide
2. Nitrogen
3. Oxygen
4. Hydrogen