question_answer 12)

The process that you saw in activity is used for purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transferred to the thin copper plate. Which electrode should be attached to the positive terminal of the battery and why?  

Answer:

The rod of impure copper plate should be connected to the positive terminal of the battery. Because when electric current is passed through the copper sulphate solution it dissociate into copper and sulphate ions. The free copper drawn to the negative terminal of the battery and get deposited on it. On the other hand the loss of copper from the solution would be regained from the impure copper rod which is connected to the positive terminal of the battery.