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During the electrolysis of copper II sulphate between pla...

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

Correct answer is D

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