$Pt(s)|{H_2}(g)(1\,bar)|{H^ + }(aq)(1\,M)||{M^{3 + }}(aq),{M^ + }(aq)|Pt(s)$

The $\mathrm{E_{cell}}$ for the given cell is 0.1115 V at 298 K when ${{\left[ {{M^ + }(aq)} \right]} \over {\left[ {{M^{3 + }}(aq)} \right]}} = {10^a}$

The value of $a$ is ____________

Given : $\mathrm{E_{{M^{3 + }}/{M^ + }}^\theta = 0.2}$ V

${{2.303RT} \over F} = 0.059V$