Which statements among the following are correct?
I. `Ce^(+4)` is an oxidizing agent & colourless.
II. `Lu^(3+)` is colourless.
III. Actinoids exhibit a higher number of oxidation states than lanthanoids.
IV. All 3d elements give `H_(2)` with 1 M HCl.

Options

A. II, III
B. I, III
C. I, II, III
D. I, IV

Answer

C

Explanation

I. `Ce^(+4)` formation favoured by its noble gas configuration, but it is a strong oxidant reverting to the common +3 state and it is colourless.
II. `Lu^(3+)` is diamagnetic and colourless.
III. Actinoids exhibit a higher number of oxidation states than lanthanoid due to lower energy difference between the consecutive 5f and 6d energy levels.
IV. All 3d elements do not give `H_(2)` with 1M HCl