The reduction potentials of four elements $P, Q, R,$ and $S$ are $-2.90 \ V, +0.34 \ V, +1.20 \ V,$ and $-0.76 \ V$ respectively. The order of decreasing reactivity is:

Identify the correct statements from the following:
$(A)$ At $298 \ K$,the potential of a hydrogen electrode placed in a solution of $pH = 10$ is $-0.59 \ V$.
$(B)$ The limiting molar conductivity of $Ca^{2+}$ and $Cl^{-}$ are $119$ and $76 \ S \ cm^2 \ mol^{-1}$ respectively. The limiting molar conductivity of $CaCl_2$ is $195 \ S \ cm^2 \ mol^{-1}$.
$(C)$ The correct relationship between $K_{c}$ and $E_{cell}^{0}$ is $E_{cell}^{0} = \frac{2.303 RT}{nF} \log K_{c}$.

Calculate the standard cell potentials of galvanic cells in which the following reactions take place:
$(i)$ $2Cr_{(s)} + 3Cd^{2+}_{(aq)} \rightarrow 2Cr^{3+}_{(aq)} + 3Cd_{(s)}$
$(ii)$ $Fe^{2+}_{(aq)} + Ag^{+}_{(aq)} \rightarrow Fe^{3+}_{(aq)} + Ag_{(s)}$
Calculate the $\Delta_r G^\Theta$ and equilibrium constant of the reactions.

Given $E_{Fe^{3+}/Fe^{2+}}^{\circ} = +0.76 \ V$ and $E_{I_{2}/I^{-}}^{\circ} = +0.55 \ V$. The equilibrium constant for the reaction taking place in a galvanic cell consisting of the above two electrodes is (Given $\frac{2.303 \ RT}{F} = 0.06 \ V$)

If $63.5 \ g$ of $Cu$ is deposited on the electrode from a $CuSO_4$ solution,what is the number of electrons involved?

The equation that is incorrect is