Q54 / 200 · NEET 2009 (Screening) · Chemistry
The stability of +1 oxidation state increases in the sequence
- Correct answerA$\mathrm{Al} < \mathrm{Ga} < \mathrm{In} < \mathrm{Tl}$
- B$\mathrm{Tl} < $ In $ < \mathrm{Ga} < \mathrm{Al}$
- C$\mathrm{In} < \mathrm{Tl} < \mathrm{Ga} < \mathrm{Al}$
- D$\mathrm{Ga} < \mathrm{In} < \mathrm{Al} < \mathrm{Tl}$
Solution
Key Idea Stability of lower oxidation states increases on moving down a group due to inert pair effect.
The given elements belong to third group. These elements mainly exhibit +3 and +1 oxidation state. As we know the stability of lower oxidation state, $i e,+1$ state, increases on moving down a group, the sequence of stability is
$$
\mathrm{Al} < \mathrm{Ga} < \mathrm{In} < \mathrm{Tl}
$$
Hence, the correct answer is option: 'A'.