Question

Given below are the half-cell reactions
$M{n}^{2+}+2e^{-}\to Mn,E^o=-1.18V$
$2(M{n}^{3+}+e^{-}\to M{n}^{2+}),E^o=+1.51V$
The $E^o$ for $3M{n}^{2+}\to Mn+2M{n}^{3+}$ will be:

• A. $-2.69V$, the reaction will not occur
• B. $-2.69V$, the reaction will occur
• C. $+3,69$, the reaction will not occur
• D. None of these

Answer 1

The correct option is A $-2.69V$, the reaction will not occur

$M{n}^{+2}+2e^{-}\to Mn\Delta G_1=-2\times f\times (-1.B)$
$2M{n}^4\to 2M{n}^3+2e^{-}\Delta n_2=-2\left(f\right)(1-51)$
$2M{n}^{2+}\to Mn+2M{n}^4$
$\Delta n_3=2\left(F\right)E=-2F\times (-1.18)-2\left(F\right)$
$E=-2.69V$