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Dry litmus papers and wet/damp/moist litmus papers were put in a gas jar containing sulphur(IV) oxide gas. State and explain the observations made

      

Dry litmus papers and wet/damp/moist litmus papers were put in a gas jar containing sulphur(IV) oxide gas. State and explain the observations made

  

Answers


Wilfred
1. Observations
(i)Dry Blue litmus paper remains blue. Dry red litmus paper remains red.
(ii) Wet/damp/moist blue litmus paper turns red. Moist/damp/wet red litmus paper remains red.
Both litmus papers are then bleached /decolorized

2. Explanation
Dry sulphur(IV) oxide gas is a molecular compound that does not dissociate/ionize to release H+(aq)ions and thus has no effect on dry blue/red litmus papers.
Wet/damp/moist litmus papers contain water that dissolves /react with dry sulphur(IV) oxide gas to form a solution of weak sulphuric(IV)acid (H2 SO3 (aq)).

Weak sulphuric(IV)acid(H2 SO3 (aq)) dissociates /ionizes into free H+(aq)ions:
H2 SO3 (aq) -> 2H+(aq) + SO32- (aq)

The free H+(aq)ions are responsible for turning blue litmus paper turns red showing the gas is acidic.
The SO32- (aq) ions in wet/damp/moist sulphur(IV) oxide gas is responsible for many reactions of the gas.
It is easily/readily oxidized to sulphate(VI) SO42- (aq) ions making sulphur(IV) oxide gas act as a reducing agent
Wilfykil answered the question on February 19, 2019 at 07:37


Next: Write the equations for the reaction for the formation of sulphur (IV)oxide using two methods
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