The process that you saw in Activity 14.7 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 battery and why?
Copper is positively charged, so it will get attracted to the negative electrode.
Because positive charges attract negative charges
As copper ions are deposited on the copper plate, the thin copper plate must be connected to the negative terminal of the battery.
Hence, the impure copper rod is connected to the positive terminal of the battery.