Question

Consider the following statements :
I. In thallium, $+1$ oxidation state is predominant.
II. In thallium, $+3$ oxidation state is oxidising in nature.
III. Compounds of group $13$ elements in $+1$ oxidation state are less ionic than those in $+3$ oxidation state.
The incorrect statement(s) is/are

• A. Only $I$
• B. Both $II$ and $III$
• C. Both $I$ and $II$
• D. Only $III$

Answer 1

Answer: (D)

Statement III is incorrect.
It's correct form is as follows :
The compounds of group-$13$ elements in $+1$ oxidation state, as expected from energy considerations, are more ionic than those in $+3$ oxidation state.
Rest other statements are correct.