Based on the following information,arrange four metals,$A$,$B$,$C$,and $D$,in order of increasing ability to act as reducing agents:
$(I)$ Only $C$ reacts with $0.10 \ M \ HCl$ to give $H_{2(g)}$.
$(II)$ When $A$ is added to a solution of the other metal ions,metallic $D$ is formed,but not $B$ or $C$.

In the electrochemical cell $H_{2(g)}, 1 \ atm \ | \ H^+_{(aq)}, 1 \ M \ || \ Cu^{2+}_{(aq)}, 1 \ M \ | \ Cu_{(s)}$,which of the following statements is true?

Give true $(T)$ and false $(F)$ for following statements :
$(1)$ There is no difference between the galvanic and the electrolytic cell.
$(2)$ In electrolytic cell,anode of galvanic cell is cathode and cathodes are anode.
$(3)$ The flow of current and electron in electrolytic cell is opposite to the galvanic cell.
$(4)$ When $2.0 \ V$ external current in the opposite direction is passed through the Daniell cell,in such condition there is no effect on Daniell cell.

Consider the following diagram in which an electrochemical cell is coupled to an electrolytic cell. What will be the polarity of electrodes $A$ and $B$ in the electrolytic cell?

On the basis of position in the electrochemical series,the metal which does not displace hydrogen from water and acid is

Under what condition is $E_{cell} = 0$ or $\Delta_r G = 0$?