Q65 / 180 · AIIMS 2005 · Chemistry
Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other, in
- Correct answerA$\mathrm{Tl}^{+}, \mathrm{Tl}^{3+}$
- B$\mathrm{Cu}^{+}, \mathrm{Cu}^{2+}$
- C$\mathrm{Cr}^{2+}, \mathrm{Cr}^{3+}$
- D$\mathrm{V}^{2+}, \mathrm{VO}^{2+}$.
Solution
$\mathrm{Tl}^{+}$ions are more stable than $\mathrm{Tl}^{3+}$ and thus, $\mathrm{Tl}^{3+}$ ions change to $\mathrm{Tl}^{+}$ions thereby acting as oxidising agents.
$\mathrm{Tl}^{3+}$ compounds $+2 e^{-} \rightarrow \mathrm{Tl}^{+}$compounds
(less stable, oxidising agent) (more stable, reducing agent)
Hence, the correct answer is option: 'A'.