Electrochemistry

Given $E_{C{l_2}/C{l^ - }}^o$ = 1.36 V, $E_{C{r^{3 + }}/Cr}^o$ = - 0.74 V $E_{C{r_2}{O_7}^{2 - }/C{r^{3 + }}}^o$ = 1.33 V, $E_{Mn{O_4}^ - /Mn ^{2+}}^o$ = 1.51 V Among the following, the strongest reducing agent is :