Give reason:

On opening a bottle of cold drink, a fizz sound is heard.

Give balanced chemical equations for the reaction of water with:

(a) Sodium

(b) Iron

(c) Carbon dioxide

(d) Sodium oxide

Name the gas produced when:

(a) steam is passed over hot coke.

(b) chlorine is dissolved in water and exposed to sunlight.

(c) a piece of calcium is added to water.

(d) when fossil fuel is burnt.

Define:

(a) Soft water

(b) Hard water