Question

Consider the following statements with respect to lanthanides:

1. The basic strength of hydroxides of lanthanides increase from $La(OH)_{3}$ to $Lu(OH)_{3}$

2. The lanthanide ions $Lu^{3 +},Yb^{2 +}$ and $Ce^{4 +}$ are diamagnetic.

Which of the statement (s) given above is/are correct?

• A. 1 only
• B. 2 only
• C. Both 1 and 2
• D. Neither 1 nor 2

Answer 1

Answer: (B)

2 only

Answer 2

Basic strength decreases from $La(OH)_{3}$ to $Lu(OH)_{3}$ hence, (1) is incorrect.

$Ce = \lbrack Xe\rbrack 4f^{1}5d^{1}6s^{2};Ce^{4 +} = \lbrack Xe\rbrack$

$Yb = \lbrack Xe\rbrack 4f^{14}6s^{2};Yb^{2 +} = \lbrack Xe\rbrack 4f^{14}$

$Lu = \lbrack Xe\rbrack 4f^{14}6s^{2};Yb^{2 +} = \lbrack Xe\rbrack 4f^{14}$

The given ions contain no unpaired electrons and therefore are diamagnetic.