Account for the following observations :
(a) In a dry cell, the build up of ammonia around the carbon cathode should disrupt the electric current, but in practice this does not happen.
(b) Ordinary dry cells are not rechargeable
1. This does not happen in practical as if the cell is allowed to rest, this ammonia diffuses toward the anode and combines with zinc ions to form a complex ion, Zn(NH3)42+ . The cell then is able to deliver a stronger current again. This is why flashlight batteries appear to run down with steady use, but to recover after standing idle for a time.
2. In a dry cell battery, the electrochemical reactions that occur at the electrodes are irreversible and hence these cannot be recharged.
2. In a dry cell battery, the electrochemical reactions that occur at the electrodes are irreversible and hence these cannot be recharged.