Question

A boy took sulphur powder on a spatula and heated it. He collected the gas

evolved by inverting a test tube over it, as shown in the figure.

(a) What will be the action of the gas on:

(i) Dry litmus paper?

(ii) Moist litmus paper?

(iii) What litmus paper will show a colour change – red or blue?

(b) Write a balanced chemical equation for the reaction taking place.​

Answer 1

Explanation:

When sulphur is heated in air it produces sulphur dioxide SO2.

(i) SO2 gas is neutral in nature and thus there will be no change in colour of dry litmus paper.

(ii) SO2 reats with water to produce H2SO3

sulphurous acid that being acid turns blue litmus paper into red litmus paper.

(b)S(s) + O2(g)— SO2(g)

SO(g) + H20(aq)—H2SO3