Question

Which of the following reaction does not involve in neither oxidation nor reduction?

• A. $V{O}^{2+}\to V_2{O}_3$
• B. $Na\to N{a}^{+}$
• C. $Cr{O}_4^{2-}\to C{r}_2{O}_7^{2-}$
• D. $Z{n}^{2+}\to Zn$

Answer 1

The correct option is C $Cr{O}_4^{2-}\to C{r}_2{O}_7^{2-}$

In (a), oxidation state of V changed from +4 to +3. Thus, it is reduction.
In (b), oxidation state of Na changed from 0 to +1. Thus it is oxidation.
In (d), Osidation state of Zn changed from +2 to 0. Thus it is reduction.
In (c),
$C{r}^{6+}\to C{r}_2^{12+};$
Cr oxidation state is not changed. Hence, neither oxidation nor reduction.