Question

Which of the following will exhibit colour in aqueous solution ?

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• A. $L{a}^{3+}(Z=57)$
• B. $S{c}^{3+}(Z=21)$
• C. $T{i}^{3+}(Z=22)$
• D. $L{u}^{3+}(Z=71)$

Answer 1

The correct option is C $T{i}^{3+}(Z=22)$

The ion which have unpaired electron shows colour
(A) $La=\left[Xe\right]5d^{1}6s^2$
$L{a}^{+3}=\left[Xe\right]$
0 unpaired electron.

(B) $Ti=\left[Ar\right]3d^{2}4s^2$
$T{i}^{+3}=\left[Ar\right]3d^1$
1 unpaired electron.

(C) $Lu=\left[Xe\right]4f^{14}5d^{1}6s^2$
$L{u}^{+3}=\left[Xe\right]4f^{14}$
0 unpaired electron.

(D) $Sc=\left[Ar\right]3d^{1}4s^2$
$S{c}^{+3}-\left[Ar\right]$
0 unpaired electron
Correct option is (b)