Q. Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below. (a) What will be the action of gas on (i) dry litmus paper? (ii) moist litmus paper? (b) Write a balanced chemical equation for the reaction taking place. What Pratyush Did
Pratyush heated sulphur powder. When sulphur is heated, it produces a gas called sulfur dioxide (SO₂).
Visual and Analogies
- Think of heating sulphur like lighting a sparkler: The solid sulphur reacts with the oxygen in the air (like the sparkler burns) and produces a gas.
- Dry litmus paper is like a dry sponge: It doesn’t react because there’s no water.
Moist litmus paper is like a wet sponge: It reacts because the gas can dissolve in the water, just like how things dissolve better in a wet sponge.
