The dand fblock elements - Result Question 39
####39. Name the gas that can readily decolourise acidified $KMnO_4$ solution :
[2017]
(a) $SO_2$
(b) $NO_2$
(c) $P_2 O_5$
(d) $CO_2$
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Solution:
- (a) Potassium permanganate has a purple colour. When sulphur dioxide reacts with potassium permanganate, the solution decolourises.
$5 SO_2+2 KMnO_4+2 H_2 O \to 2 H_2 SO_4+2 MnSO_4$ $+K_2 SO_4$
