Consider the following statements in respect of lanthanides, which of the statements are incorrect?
(i) \(\mathrm{La}(\mathrm{OH})_3\) is least basic among the hydroxides of lanthanides
(ii) The lanthanide ions \(\mathrm{Yb}^{2+}, \mathrm{Lu}^{3+}\) and \(\mathrm{Ce}^{4+}\) are diamagnetic in nature.
(iii) \(\mathrm{Ce}^{4+}\) can act as an oxidising agent
(iv) \(\operatorname{Ln}\) (III) compounds are generally colourless
(v) Ionic radii of \(\mathrm{Ce}^{3+}\) is greater than \(\mathrm{Yb}^{3+}\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.