Question

Which species is acting as a reducing agent in the following reaction ?
$14H^{+}+C{r}_2{O}_7^{2-}+3Ni\to 2C{r}^{3+}+7H_{2}O+3N{i}^{2+}$

• A. $C{r}_2{O}_7^{2-}$
• B. Ni
• C. $H^{+}$
• D. $H_{2}O$

Answer 1

The correct option is B Ni

Reducing agent is defined as the species which carries out the reduction of other species and itself gets oxidized.

In the reaction given in option B, the charge on nickel atom is changed from $0$ to $+2$. Thus Nickel atom is oxidized and it carries out the reduction of Chromium atom.

$14H^{+}+C{r}_2{O}_7^{2-}+3Ni\to {2Cr}^{3+}+7H_{2}O+3N{i}^{2+}$

Oxidation: $Ni\to N{i}^{2+}$

Reduction: $C{r}^{6+}\to C{r}^{3+}$