Question

The values for Cr, Mn, Fe and Co are – 0.41, + 1.57, + 0.77 and + 1.97 V respectively. For which one of these metals, the change in oxidation state from +2 to +3 is easiest

• A. Cr
• B. Mn
• C. Fe
• D. Co

Answer 1

Answer: (A)

Cr

Answer 2

$Cr^{2 +}lCr^{3 +} = + 0.41V$

$Mn^{2 +}lMn^{3 +} = - 1.57V$

$Fe^{2 +}lFe^{3 +} = - 0.77V$

$Co^{2 +}lCo^{3 +} = - 1.97V$

As Cr will have maximum oxidation potential value, therefore its oxidation will be easiest