Question

The disadvantage of voltaic cells are ________ and ______.

• A. polarization
• B. local effect

Answer 1

1. In the voltaic cells, the amount of hydrogen gas formed at the copper plate increases which forms a layer of hydrogen gas over the copper electrode and blocks the charge flow. Because of this potential difference between electrodes and electric current decreases with time. This effect is known as polarization.
2. In voltaic cells, if any other metal is present as impurities instead of zin on the zinc plate, the chemical reactions take place continuously in the cell, which causes the zinc plate to erode out faster than the electric current is extracted in external conducting wires. This causes a loss in electric current. This effect is called the local effect.

Hence, the disadvantages of voltaic cells are polarization and local effect.