Question

Which of the following reactions does not involve either oxidation or reduction?

• A. $V{O}^{2+}⟶V_2{O}_3$
• B. $Na⟶{Na}^{\oplus }$
• C. $Cr{O}_4^{2-}⟶{Cr}_2{O}_7^{2-}$
• D. ${Zn}^{2+}⟶Zn$

Answer 1

Answer: (C)

$Cr{O}_4^{2-}⟶{Cr}_2{O}_7^{2-}$

Following reaction does not involve either oxidation or reduction.

$Cr{O}_4^{2-}⟶{Cr}_2{O}_7^{2-}$
The oxidation state of Cr in both side is same i.e. $+6$.