Complete the following word equations :

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

How would you obtain 'hydrogen from sodium hydroxide' solution other than by electrolysis ?

What do the following symbols represent : 2H and H₂.

Write balanced equation of the reaction in the preparation of : hydrogen from a solution of potassium hydroxide [other than by electrolysis].