$Cu^{2+}$ ions will be reduced to $Cu^{+}$ ions by the addition of an aqueous solution of

Which of these statements is not true?

Four successive members of the first row transition elements are listed below with their atomic numbers. Which of these elements has the maximum $E^o_{M^{3+}/M^{2+}}$ value?

The highest oxidation state of manganese in fluorides is $+4$ $(MnF_4)$, but the highest oxidation state in oxides is $+7$ $(Mn_2O_7)$, because

For $Cr, Mn, Fe,$ and $Co$,the $E^{0}_{M^{3+}/M^{2+}}$ values are $-0.41, +1.57, +0.77,$ and $+1.97 \ V$ respectively. For which metal is the change in oxidation state from $+2$ to $+3$ the easiest?

The highest Mn fluoride is $MnF_4$ whereas the highest oxide is $Mn_2O_7$, because . . . . . . .