Which one of the following statements related to lanthanoids is incorrect -

Options

A. Ce (+4) solutions are widely used as oxidising agent in volumetric analysis
B. europium shows + 2 oxidation state
C. the basicity decreases as the ionic radius decreases from Pr to Lu
D. all the lanthanoids are much more reactive than aluminium

Answer

A, B, C

Explanation

All are correct.
A : `Ce^(4+)` is a strong oxidising agent as it readily reduces to stable `Ce^(3+)` ion.
B : `Eu(4f^(7)6s^(r ))` easily gives up two electrons and forms `Eu^(2+)` ion.
C : As ionic radii decreases from Pr to Lu, the covalent character of their hydroxide gradually increases and basicity decreases.
D : For lanthanoid elements, `E_(M^(3+)|M)^(0)` value is highly negative compared to that of Al. Thus lanthonoids are more electropositive than Al and are more reactive than Al.