Extraction of Metals - Result Question 43
####43. Copper is purified by electrolytic refining of blister copper. The correct statement(s) about this process is/are (2015 Adv.)
(a) impure $Cu$ strip is used as cathode
(b) acidified aqueous $CuSO _4$ is used as electrolyte
(c) pure $Cu$ deposits at cathode
(d) impurities settle as anode-mud
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Solution:
- (a) is wrong statement. Impure copper is set as anode where copper is oxidised to $Cu^{2+}$ and goes into electrolytic solutions.
(b) $CuSO _4$ is used as an electrolyte in purification process.
(c) Pure copper is deposited at cathode as:
$$ Cu^{2+}+2 e^{-} \longrightarrow Cu: \quad \text { (At cathode) } $$
(d) Less active metals like $Ag$, $Au$ etc settle down as anode mud.
