Question

Match the complexes in Column I with their properties listed in Column II.

Column I		Column II
(A)	$\left[Co{\left(N{H}_3\right)}_4{\left(H_{2}O\right)}_2\right]C{l}_2$	(p)	geometrical isomers
(B)	$\left[Pt{\left(N{H}_3\right)}_{2}C{l}_2\right]$	(q)	paramagnetic
(C)	$\left[Co{\left(H_{2}O\right)}_{5}Cl\right]Cl$	(r)	diamagnetic
(D)	$\left[Ni{\left(H_{2}O\right)}_6\right]C{l}_2$	(s)	metal ion with$+2$ oxidation state

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

Answer 1

Answer: (A)

$(A)\to p,q,s;(B)\to p,r,s;(C)\to q,s;(D)\to q,s$
In all the complexes, the oxidation state of central metal ion is $+2$. Any complex with molecular formula $M{A}_2{B}_2$ shows geometrical isomerism. Moreover, valence shell electron configuration of $C{o}^{2+}$ in $\left[Co{\left(N{H}_3\right)}_4{\left(H_{2}O\right)}_2\right]C{l}_2,\left[Co{\left(H_{2}O\right)}_{5}Cl\right]Cl$ and $N{i}^{2+}$ in $\left[Ni{\left(H_{2}O\right)}_6\right]C{l}_2$ (all are attached to weak field ligands) suggest that there are unpaired electrons (paramagnetic) whereas $P{t}^{2+}$ do not have any unpaired electrons, hence, it is diamagnetic.