MCQ
Which one of the following conversions does not involve either oxidation or reduction?
- A$\mathrm{VO}_2^{+} \longrightarrow \mathrm{V}_2 \mathrm{O}_3$
- B$\mathrm{Na} \longrightarrow \mathrm{Na}^{+}$
- ✓()) $\mathrm{CrO}_4^{2^{-}} \longrightarrow \mathrm{Cr}_2 \mathrm{O}_7^{2-}$
- D$\mathrm{Zn}^{2+} \longrightarrow \mathrm{Zn}$