Question

Consider the following statements.
I. $La(OH{)}_3$ is the least basic among hydroxides of lanthanides.
II. $Z{r}^{4+}$ and $H{f}^{4+}$ possess almost the same ionic radii.
III. $C{e}^{4+}$ can act as an oxidising agent.
Which of the above is/are true?

• A. I and III
• B. II and III
• C. II only
• D. I and II

Answer 1

Answer: (B)

II and III

The basic character of hydroxides decreases from $La(OH{)}_3$ to $Lu(OH{)}_3$. Due to the smaller size of $Lu$, the $Lu-OH$ bond attains more covalent character. $La(OH{)}_3$ is the most basic among hydroxides of lanthanoids.

$Z{r}^{4+}$ and $H{f}^{4+}$ possess almost the same ionic radii.

$C{e}^{4+}$ can act as an oxidising agent as it can accept an electron to reduce its oxidation state to $+3$.

Statement II and III are true.