The maximum work that can be obtained from the following cell is
$X|X^{2+}_{(aq)} || Y^{+}_{(aq)}| Y$
Given,$E^{\circ}_{X^{2+}/X} = -1.7 \ V, E^{\circ}_{Y^{+}/Y} = 0.8 \ V$

For the reaction $Cu^{2+}_{(aq)} + Fe_{(s)} \rightleftharpoons Fe^{2+}_{(aq)} + Cu_{(s)}$,calculate $\Delta G^o$ in Joules.
Given: $E^o_{Cu^{2+}/Cu} = +0.34 \ V$,$E^o_{Fe^{2+}/Fe} = -0.44 \ V$.

The standard reduction potentials at $298 \ K$ for the following half-cells are given below:
$Cr_2O_7^{2-} + 14H^+ + 6e^- \rightarrow 2Cr^{3+} + 7H_2O$,$E^{\circ} = 1.33 \ V$
$Fe^{3+} + 3e^- \rightarrow Fe$,$E^{\circ} = -0.04 \ V$
$Ni^{2+} + 2e^- \rightarrow Ni$,$E^{\circ} = -0.25 \ V$
$Ag^+ + e^- \rightarrow Ag$,$E^{\circ} = 0.80 \ V$
$Au^{3+} + 3e^- \rightarrow Au$,$E^{\circ} = 1.40 \ V$
Consider the given electrochemical reactions. The number of metal$(s)$ which will be oxidized by $Cr_2O_7^{2-}$ in aqueous solution is $.....$

$A$ saturated solution of $KNO_3$ with agar-agar is used to make a 'salt-bridge' because

Give advantages of fuel cell.

The cell reaction of the galvanic cell $Cu_{(s)} | Cu^{2+}_{(aq)} || Hg^{2+}_{(aq)} | Hg_{(l)}$ is