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

Options

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

Answer

C

Explanation

Most of the trivalent lanthanoid compounds except that of `La^(3+)` and `Lu^(3+)` are coloured both in the solid state and in the aqueous solution. The colour of these ions can be attributed due to the presence of f-electrons.