For the cell $Co|Co^{2+}(C_2)||Co^{2+}(C_1)|Co$,$\Delta G$ is negative if

$Pt_{(s)} | H_{2(g)} (1 \ atm) | H^{+} (pH = 2) || H^{+} (pH = 3) | H_{2(g)} (1 \ atm) | Pt_{(s)}$ cell reaction will be

For the cell reaction $Zn(s) + Cu^{2+}(aq) (1.0 \, M) \to Cu(s) + Zn^{2+}(aq) (0.1 \, M)$,the measured $e.m.f.$ at $25 \, ^oC$ is $1.3 \, V$. Calculate the $E^o$ value for the cell reaction. (in $, V$)

$Zn_{(s)} + Cl_2(1 \ atm) \to Zn^{2+} + 2Cl^-$. The $E^0_{cell}$ of the cell is $2.12 \ V$. To increase $E_{cell}$:

The $\text{EMF}$ of a galvanic cell consisting of two hydrogen electrodes is $0.17 \ V$. If the solution of one of the electrodes has $[H^+] = 10^{-3} \ M$,the $\text{pH}$ at the other electrode is:

The $EMF$ of the following three galvanic cells are $E_1, E_2$ and $E_3$ respectively. Which of the following is correct?
$(i)$ $Zn | Zn^{2+} (1 \ M) || Cu^{2+} (0.1 \ M) | Cu$
$(ii)$ $Zn | Zn^{2+} (1 \ M) || Cu^{2+} (1 \ M) | Cu$
$(iii)$ $Zn | Zn^{2+} (0.1 \ M) || Cu^{2+} (1 \ M) | Cu$