(i) Polarization - accumulation of bubbles around the copper plate (positive plate). This defect provides insulation to the flow of current and also sets up some “local” cells with copper whose electron flow tends to oppose the flow of electrons from the zinc plate. The overall effect is increase in the internal resistance of the cell, which reduces the flow of current.
(ii) Local action - the zinc plate is depleted (eaten away) as it reacts with dilute sulphuric acid. Impurities in zinc promote local action.
chrispohmomanyi answered the question on September 18, 2017 at 16:15
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