Question

Match Column-I with Column-II

Column I (Complexes)		Column II (Absorbed Light)
A	${\left[N{i}_2{\left(H_{2}O\right)}_4(en)\right]}^{2+}(aq)$	p	Yellow Orange
B	${\left[Ni{\left(H_{2}O\right)}_4(en{)}_2\right]}^{2+}(aq)$	q	Blue-Green
C	${\left[Ni(en{)}_3\right]}^{2+}(aq)$	r	Red

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

Answer 1

Answer: (D)

Crystal field splitting energy increases with increase in ligand field strength i.e., with increase in no. of 'en' groups and wavelength of absorbed light decrease with increase in ligand field strength
$\therefore {\left[N{i}_2{\left(H_{2}O\right)}_4(en)\right]}^{2+}(aq)$ will absorb light of higher wavelength i.e., Red.
${\left[Ni(en{)}_3\right]}^{2+}$ will absorb light of lower wavelength i.e., bluegreen and ${\left[Ni{\left(H_{2}O\right)}_4(en{)}_2\right]}^{2+}$ will absorb yellow orange light.