Question

Out of the ions $A{g}^{+},C{o}^{2+},T{i}^{4+}$, which one will be coloured in aqueous solutions.

[Atomic no : Ag = 47, Co = 27, Ti = 22]

• A. $A{g}^{+}$
• B. $C{o}^{2+}$
• C. $T{i}^{4+}$
• D. None of these

Answer 1

The correct option is B $C{o}^{2+}$

compound with unpaired d-electron will show color.

$A{g}^{+}=5d^{10},n=0$

$T{i}^{+4}=3s^{2}3p^6,n=0$

$C{o}^{+2}=\left[Ar\right]3d^7,n=3$ It will show color due to unpaired d electrons.