Question

The correct order of $E^0{M}^{2+}/M$ values with negative sign for the four successive elements Cr, Mn, Fe and Co is

• A. Fe$>$Mn$>$Cr$>$Co
• B. Cr$>$Mn$>$Fe$>$Co
• C. Mn$>$Cr$>$Fe$>$Co
• D. Cr$>$Fe$>$Mn$>$Co.

Answer 1

The correct option is C Mn$>$Cr$>$Fe$>$Co

$E^0$ values of $M^{2+}/M$ with negative sign are: Cr=-0.91V, Mn= -1.18V, Fe=-0.44V,Co= -0.28V. Thus, the order is Mn$>$Cr$>$Fe$>$ Co.