State the products of the reaction 'when steam is passed over red-hot iron'.

How can you obtain hydrogen from a mixture of hydrogen and carbon monoxide.

Give reasons for the following :

'Though hydrogen is lighter than air, it is not collected by the downward displacement of air'.

Complete the following word equations :

(i) Sodium hydroxide + zinc ⟶ hydrogen + ……………
(ii) Calcium + water ⟶ calcium hydroxide + ……………