Chemistry - Electrochemistry Question with Solution | TestHub

Since, ${\mathrm{H}}_2{\mathrm{SO}}_4$ and ${\mathrm{H}}_3{\mathrm{PO}}_4$, both are strong acids so their presence makes the medium more acidic. The ${\mathrm{Fe}}^{3+}$ ions form complex, IFeHPO ${{}_4]}^{+}$ with these acid and hence, the concentration of ${\mathrm{Fe}}^{3+}$ ion reduces which results in lowering in the formal reduction potential.