Q3 / 125 · BITSAT 2016 · Chemistry

Knowing that the chemistry of lanthanoids(Ln) is dominated by its +3 oxidation state, which of the following statements is incorrect?

A
The ionic size of Ln (III) decrease in general with increasing atomic number
Correct answer
B
Ln (III) compounds are generally colourless.
C
Ln (III) hydroxide are mainly basic in character.
D
Because of the large size of the Ln (III) ions the bonding in its compounds is predominantly ionic in character.

Solution

Most of the $\mathrm{Ln}^{3+}$ compounds except $\mathrm{La}^{3+}$ and $\mathrm{Lu}^{3+}$ are coloured due to the presence of $f$ -electrons.

Hence, the correct answer is option: 'B'.

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