Extraction of Metals - Result Question 21
####21. The metal that cannot be obtained by electrolysis of an aqueous solution of its salts is
(2014 Main)
(a) $Ag$
(b) $Ca$
(c) $Cu$
(d) $Cr$
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Solution:
- Higher the position of element in the electrochemical series more difficult is the reduction of its cations.
If $Ca^{2+}(a q)$ is electrolysed, water is reduced in preference to it. Hence, it cannot be reduced electrolytically from their aqueous solution.
$$ Ca^{2+}(a q)+H _2 O \longrightarrow Ca^{2+}+OH^{-}+H _2 \uparrow $$
