MHTCET 17 Apr 2026 Shift 2 Paper

Concept:A cell reaction is spontaneous when its standard cell potential $E_{\text{cell}}^\circ$ is positive, and non-spontaneous when it is negative.Explanation:Use the formula $E_{\text{cell}}^\circ = E_{\text{cathode}}^\circ - E_{\text{anode}}^\circ$.In option A, $\mathrm{Fe}^{2+}$ is reduced at the cathode and $\mathrm{Ag}$ is oxidised at the anode.So $E_{\text{cell}}^\circ = (-0.44) - (+0.79) = -1.23\ \mathrm{V}$.Since $E_{\text{cell}}^\circ < 0$, option A is non-spontaneous.Check the other options for confirmation:Option B: $E_{\text{cell}}^\circ = 0.34 - (-1.66) = +2.00\ \mathrm{V}$.Option C: $E_{\text{cell}}^\circ = 0.34 - (-0.44) = +0.78\ \mathrm{V}$.Option D: $E_{\text{cell}}^\circ = -0.44 - (-1.66) = +1.22\ \mathrm{V}$.All three are positive, so they are spontaneous.Remember that stoichiometric coefficients do not change the electrode potential values.Answer:The non-spontaneous reaction is given in Option A.