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

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

Ln (III) compounds are generally colourless

$Ln(III)$ compounds are coloured due to the $f-f$ transitions in the lanthanoids but the colour is fainter as compared to the $d-d$ transitions in transition metals.