Efficiency of the following cell is $84\%$. $A_{(s)} + B^{2+}(aq.) \rightleftharpoons A^{2+}(aq.) + B_{(s)}$; $\Delta H^o = -285 \ kJ$. Then the standard $EMF$ of the cell will be ........... $V$.

Which of the following statements is incorrect?

Given the values of $ᴧ^{0}$ for $KCl, KNO_3, HCl, NaOAc,$ and $NaCl$ are $149.9, 146.0, 426.2, 91.0,$ and $226.5 \, S \, cm^2 \, eq^{-1}$ respectively,calculate the value of $ᴧ^{0}$ for $HOAc$.

Calculate the $K_C$ and $\Delta G^o$ for the chemical reaction :
$Ni_{(s)} + 2Ag_{(aq)}^{+} \to Ni_{(aq)}^{2+} + 2Ag_{(s)}$ $ [E^o = 1.05 \, V] $

The molar conductivity of acetic acid solution at infinite dilution is $390 \ S \ cm^2 \ mol^{-1}$. What is the molar conductivity of $0.01 \ M$ acetic acid solution (in $S \ cm^2 \ mol^{-1}$)? (Given: $K_{a}(CH_3COOH) = 1.8 \times 10^{-5}$,assume $1-\alpha \approx 1$)

The conductivity of $0.001028 \, mol \, L^{-1}$ acetic acid is $4.95 \times 10^{-5} \, S \, cm^{-1}$. Calculate its dissociation constant if $\Lambda_m^\circ$ for acetic acid is $390.5 \, S \, cm^2 \, mol^{-1}$.