Question

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

Answer 1

The correct option is B $Ni$

$14H^{+}+C{r}_2{O}_7^{2-}+3Ni\to 2C{r}^{3+}+7H_{2}O+3N{i}^{2+}$
+6 0 +3 +2
As Ni is oxidised from $0$ to $+2$, it will acts as reducing agent.