pBlock ElementsII - Result Question 93
89. Give reasons in two or three sentences only. Sulphur dioxide is a more powerful reducing agent in the alkaline medium than in acidic medium.
(1992, 2M)
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Solution:
$SO _2$ acts as reducing agent on account of following reaction :
$SO _2+2 OH^{-} \longrightarrow SO _4^{2-}+2 H^{+}+2 e^{-}$
Hence, the above reaction proceeds in forward direction on increasing concentration of $HO^{-}$ion. $H^{+}$is on product side, adding $H^{+}$retards the reaction by sending it in backward direction.