Question

Arrange the following compounds in order of their molar conductance:
(i) $K\left[Co\right(N{O}_2{)}_4\left(N{H}_3{)}_2\right]$
(ii) $\left[Cr\right(ONO{)}_3\left(N{H}_3{)}_3\right]$
(iii) $\left[Cr\right(N{O}_2\left)\right(N{H}_3{)}_5{]}_3\left[Co\right(N{O}_2{)}_6{]}_2$
(iv) $Mg\left[Cr\right(N{O}_2{)}_5\left(N{H}_3\right)]$

• A. (ii) < (i) < (iv) < (iii)
• B. (i) < (ii) < (iii) < (iv)
• C. (ii) < (i) < (iii) < (iv)
• D. (iv) < (iii) < (ii) < (i)

Answer 1

Answer: (A)

(ii) < (i) < (iv) < (iii)

The molar conductivity of the complex compounds depends on the number of the ions they give in solution on dissociation and the charge on each ion.
Greater is the number of ions or greater is the charge on each ion, greater will be the molar conductivity.
The increasing order of the molar conductivities of the compounds is $\left(ii\right)<\left(i\right)<\left(iv\right)<\left(iii\right)$

$\left[Cr\right(ONO{)}_3\left(N{H}_3{)}_3\right]<K\left[Co\right(N{O}_2{)}_4\left(N{H}_3{)}_2\right]<Mg\left[Cr\right(N{O}_2{)}_5\left(N{H}_3\right)]<[Cr\left(N{O}_2\right)\left(N{H}_3{)}_5{]}_3\right[Co(N{O}_2{)}_6{]}_2$.