Electrolytic Refining

Q.

Explain the reasons:

1. In the electrolytic reduction of alumina, the graphite anode is gradually consumed.
2. Roasting is carried out on sulphide ores and not on carbonate ores.
3. Carbon can reduce lead oxide but not aluminium oxide.

Q. In the electrolytic refining of copper using $CuS{O}_4$ as the electrolyte, the anode reaction is

1. $4O{H}^{-}\left(aq\right)\to O_2\left(g\right)+2H_{2}O\left(l\right)+4e^{-}$
2. $C{u}^{2+}\left(aq\right)+2e^{-}\to Cu\left(s\right)$
3. $2S{O}_4^{2-}\left(aq\right)\to S_2{O}_8^{2-}\left(aq\right)+2e^{-}$
4. $Cu\left(s\right)\to C{u}^{2+}\left(aq\right)+2e^{-}$

Q.

In the electrolytic refining of Copper (electrolyte is $CuS{O}_4$ solution + dil $H_{2}S{O}_4$ _;Pure Cu cathode and Impure Cu anode), metallic impurities having lower oxidation potential than Cu are deposited as __ sludge.

Q. In the electrolytic refining of copper using $CuS{O}_4$ as the electrolyte, the anode reaction is

1. $4O{H}^{-}\left(aq\right)\to O_2\left(g\right)+2H_{2}O\left(l\right)+4e^{-}$
2. $C{u}^{2+}\left(aq\right)+2e^{-}\to Cu\left(s\right)$
3. $2S{O}_4^{2-}\left(aq\right)\to S_2{O}_8^{2-}\left(aq\right)+2e^{-}$
4. $Cu\left(s\right)\to C{u}^{2+}\left(aq\right)+2e^{-}$

Q.

In electrolytic refining, the impure metal acts as anode.

1. True

2. False