Consider the following statements.
(I) La(OH)₃ is the least basic among hydroxides of lanthanides.
(II) Zr⁴⁺ and Hf⁴⁺ possess almost the same ionic radii.
(III) Ce⁴⁺ can act as an oxidizing agent.
Which of the above statements is incorrect?

Question

Consider the following statements.

(I) La(OH)₃ is the least basic among hydroxides of lanthanides.

(II) Zr⁴⁺ and Hf⁴⁺ possess almost the same ionic radii.

(III) Ce⁴⁺ can act as an oxidizing agent.

Which of the above statements is incorrect?

TestHub · Accepted Answer

Question Explanation: The question is asking to select the incorrect statement. Concept: This question is based on lanthanide and d-block properties.

Solution:

(1) Basic nature of hydroxide $\propto \frac{1}{EN} \propto \frac{1}{Zeff}$

(2) $Zr^{4 \oplus} & Hf^{4 \oplus}$ same size due to lanthanide contraction

(3) $Ce^{4 \oplus} + e ⊖ \to Ce^{3 \oplus} (Ce^{3 \oplus}$ is stable so it can act as oxidising agent)

Chemistry - f-block Question with Solution | TestHub