NCERT Solution for Class Tenth Science Chapter 3
Metals and Non-metals
CBSE NCERT Book Session-2022-2023
Exercises Questions
Page No-20
Questions No-9
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.
(a) (i) There will be no action on dry litmus paper.
(ii) Since the gas is sulphur dioxide (SO₂), it turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid.
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(a) (i) No change will be on dry Litmus paper.
(ii) The gas is sulphur dioxide (SO2), which turns moist blue litmus paper to red because sulphur dioxide reacts with moisture to form sulphurous acid.
(b) S(s) + O2(g) → SO2(g)
Sodium dioxide
SO2(g) + H2O(f) → H2SO3(aq)
Sulphurous acid