Which substance is reduced in a dry cell?

Write reactions for the followings :
$1.$ Anode reaction of dry cell.
$2.$ Reduction reaction of dry cell.

The reaction $\frac{1}{2} H_{2(g)} + AgCl_{(s)} \rightleftharpoons H^{+}_{(aq)} + Cl^{-}_{(aq)} + Ag_{(s)}$ occurs in which of the given galvanic cell?

In animals,nerve signals are generated due to which of the following?

Which of the following is used to avoid leakage of electrolyte in a dry cell?

What is electrochemistry? Give the uses of electrochemistry.