Of the following, the metals that cannot be obtained byelectrolysis of the aqueous solution of their salts are : (1990 - 1 Mark)
Both Mg and Al have their reduction potentials less than that of water [Eº = –0.83 V]. Hence, their ions in the aqueous solution can not be reduced. Instead water will be reduced : 2H2O + 2e– → H2 + 2OH–
Extraction of metal from the ore cassiterite involves (2011)
The carbon-based reduction method is NOT used for the extraction of (JEE Adv. 2013)
Al from Al2O3 and Mg from MgCO3.CaCO3 are separately extracted by electrolytic reduction.
Upon heating with Cu2S, the reagent(s) that give coppermetal is/are (JEE Adv. 2014)
Cu2S + 2Cu2O → 6Cu + SO2
Cu2S + 2CuO → 4Cu + SO2
Cu2S + CuSO4 → 3Cu + 2SO2
Copper is purified by electrolytic refining of blister copper.The correct statement(s) about this process is(are) (JEE Adv. 2015)
In electrolytic refining of blister Cu, acidified CuSO4 is used as electrolyte, pure Cu deposits at cathode and impurities settle as anode mud.
Extraction of copper from copper pyrite (CuFeS2) involves (JEE Adv. 2016)
Refining of blister copper is done by poling followed by electrorefining but not by carbon reduction method.