During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment,
A
the litmus turns blue but no gas is evolved
B
the litmus turns blue and oxygen is evolved
C
the litmus turns blue and hydrogen is evolved
D
the litmus turns red and oxygen is evolved
E
the litmus turns red and then becomes colourless
Verified Correct Answer: D.
Chemical Principles & Mechanism
Cu\(^+\) is discharged preferentially at the cathode
OH\(^-\) is discharged preferentially at the anode
The presence of SO\(_4\)\(^2-\) and H\(^+\) makes the medium acidic
Which makes the litmus turns red and oxygen is evolved
Source: Myschool Past Questions Archive (Record #58)