Chemistry - f-block Question with Solution | TestHub

The basic strength of the hydroxides decreases as we move from cerium to lutetium Also the lanthanoid hydroxides are more basic than$\mathrm{A}\mathrm{l}{\left(\mathrm{O}\mathrm{H}\right)}_3$but less basic than$\mathrm{C}\mathrm{a}{\left(\mathrm{O}\mathrm{H}\right)}_2$.

$\mathrm{B}{\left(\mathrm{O}\mathrm{H}\right)}_3$is more covalent than$\mathrm{A}\mathrm{l}{\left(\mathrm{O}\mathrm{H}\right)}_3.\mathrm{B}\mathrm{e}{\left(\mathrm{O}\mathrm{H}\right)}_2$is as covalent as$\mathrm{A}\mathrm{l}{\left(\mathrm{O}\mathrm{H}\right)}_3$.

$\mathrm{B}{\left(\mathrm{O}\mathrm{H}\right)}_3$is acidic while$\mathrm{B}\mathrm{e}{\left(\mathrm{O}\mathrm{H}\right)}_2$and$\mathrm{A}\mathrm{I}{\left(\mathrm{O}\mathrm{H}\right)}_3$are amphoteric while all others are more basic than$\mathrm{A}\mathrm{I}{\left(\mathrm{O}\mathrm{H}\right)}_3$.

Hence choice$\left(\mathrm{B}\right)$is correct while$\left(\mathrm{A}\right),\left(\mathrm{B}\right)\mathrm{ }\mathrm{a}\mathrm{n}\mathrm{d}\mathrm{ }\left(\mathrm{D}\right)$are incorrect.