Question

Iqbal treated a lustrous, divalent element M with sodium hydroxide. He observed the formation of bubbles in the reaction mixture. He made the same observations when this element was treated with hydrochloric acid.

Suggest how can he identify the produced gas. Write chemical equations for both the reactions.

Answer 1

Since it is a lustrous, divalent element that reacts with both acids and bases, it is a metal. When a metal is treated with a base or an acid, it releases hydrogen gas.

In the mentioned reactions, the produced gas can be identified as hydrogen by bringing a glowing matchstick near the reaction vessel. Production of a pop sound is a confirmatory observation.

The pop sound represents a minor explosion on combustion of inflammable hydrogen gas.

$M\left(s\right)+2NaOH\left(aq\right)\to N{a}_{2}M{O}_2\left(aq\right)+H_2\left(g\right)M\left(s\right)+2HCl\left(aq\right)\to MC{l}_2+H_2\left(g\right)$