Question

Match Column-I with Column-II.

Column I		Column II
A	Lanthanide hard as steel.	p	Lu
B	Lanthanide with maximum paramagnetic character in $Ln^{4+}$ state.	q	Tb
C	Lanthanide with maximum value of $E^{\circ}$ for reaction $Ln^{3+} (aq)+3e^- \rightarrow Ln(s)$.	r	Sm
D	Lanthanide whose $Ln^{3+}$ ion is diamagnetic in nature	s	Eu

• A. A - (r), B - (s), C - (p), D - (q)
• B. A -(r),B -(q ), C -(s ),D -(p )
• C. A - (s), B - (r), C - (q), D - (p)
• D. A - (r), B - (s), C - (q), D - (p)

Answer 1

Answer: (B)

(A) Sm is hard as steel.
(B) $Tb ^{4+}$ has $4 f^7$ configuration $(7$ unpaired electrons) and thus maximum paramagnetic character.
(C) $Eu$ has maximum value of $E^{\circ}$ for reaction:
$E_{ u }^{3+}( aq )+3^{-} \rightarrow Eu (s) ; E^{\circ}=-2.0 \,V$.
(D) $Lu ^{3+}$ is diamagnetic as it has $4 f^{14}$ configuration.