Question

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 the figure.
What will be the action of gas on dry litmus paper?

• A. It turns blue litmus paper to red
• B. It turns red litmus paper to blue
• C. There will be no action
• D. None of these

Answer 1

Answer: (C)

There will be no action

Burning sulphur produces a gas which is sulphur dioxide gas. It is confirmed by following experiments.
1) This gas has no effect on dry litmus paper.
2) On a moist litmus paper this gas converts blue litmus to red litmus paper as sulphur dioxide gas formed is acidic in nature and on reacting with moist paper it forms sulphurous acid.
$S\left(s\right)+O_2\left(g\right)\to {SO}_2\left(g\right)$