In the cell represented as $Ni_{(s)}|Ni_{(1M)}^{2+}||Ag_{(1M)}^{+}|Ag_{(s)}$,the reducing agent is

What is the reaction when a $Zn$ rod is kept in a copper nitrate solution?

In a Mercury cell,which of the following acts as a cathode?

Write a note on hydrogen-oxygen fuel cell.

Colourless solutions of the following four salts are placed separately in four different test tubes and a strip of copper is dipped in each one of these. Which solution will turn Blue?

The efficiency of a fuel cell is given by