50 mL of $0.1\mathrm{M}{\mathrm{Fe}}^{2+}$ is titrated at 298 K against $0.1\mathrm{M}{\mathrm{Ce}}^{4+}$ ions in an acidic medium. Given:

$\begin{array}{l}{\mathrm{Ce}}^{4+}\left(\mathrm{aq}\right)+{\mathrm{e}}^{-}\to {\mathrm{Ce}}^{3+}\left(\mathrm{aq}\right);\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}{E}^{\circ }=1.46\mathrm{V}\\ {\mathrm{Fe}}^{3+}\left(\mathrm{aq}\right)+{\mathrm{e}}^{-}\to {\mathrm{Fe}}^{2+}\left(\mathrm{aq}\right);\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}\hspace{0.25em}{E}^{\circ }=0.70\mathrm{V}\end{array}$

The potential $E\left({\mathrm{Fe}}^{3+},{\mathrm{Fe}}^{2+}\mid \mathrm{Pt}\right)$ after the addition of 10 mL of ${\mathrm{Ce}}^{4+}$ solution is