When `CuSO_(4)` is electrolysed, using Pt electrodes

Options

A. copper is deposited at cathode, sulpher is liberates at anode
B. copper is deposited at cathode, oxygen gas is liberated at andoe
C. oxygen gas is liberated at cathode, copper is deposited at anode
D. sulphur is deposited at cathode, oxygen gas is liberated at anode

Answer

B

Explanation

Unless it is specified, we assume the solution to be concentrated. At cathode, copper is deposited on account of higher reduction potential: `Cu^(2+) + 2e^(-) rarr Cu` At anode, `O_(2)` gas is liberated on a account of lower reduction potential of water: `2H_(2)O rarr O_(2) + 4H^(+) + 4e^(-)`