QJEEM17Ch88e0: JEE Main 2017 Chemistry - Class 12 JEEM17Ch88e0 Solution: To find the standard potential of M 3+ /M electrode,the…

According to Nernst equation, for the cell reaction

M(s) + 3Ag⁺(aq) $\to$ M³⁺(aq) + 3Ag(s)

${E_{cell}} = E_{cell}^o - {{0.059} \over n}\log {{[{M^{3 + }}]} \over {{{[A{g^ + }]}^3}}}$

Substituting the values, we get

$0.421 = E_{cell}^o - {{0.059} \over 3}\log {{0.001} \over {{{(0.01)}^3}}}$

$E_{cell}^o = 0.48V$

We know that $E_{cell}^o = E_{A{g^ + }/Ag}^o - E_{{M^{3 + }}/M}^o$

$0.48 = 0.8 - E_{{M^{3 + }}/M}^o$

$E_{{M^{3 + }}/M}^o = 0.32V$