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
jamb 1978chemistry

The correct answer is D. the litmus turns red and oxygen is evolved

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

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