c
વોન્ટ હોફ અવયવ \({\text{(2)}}\,\,\, = \,\,\frac{{{\text{calculated}}\,{\text{mol}}{\text{.wt}}}}{{observrd\,mol.wt}}\)

\( = \,\,\frac{{164}}{{65.6}}\,\, = \,\,2.5\)

\(\because \,\,i\,\, = \,\,1\,\, + \,\,(n\,\, - \,\,1)\,\,\alpha .\,[Ca{(N{O_3})_2} \to \,\,C{a^{ + 2}}\, + \,\,2NO_3^ - ]\)

\(2.5\,\, = \,\,1\,\, + \,\,(3\,\, - \,\,1)\,\,\alpha \,\,\, \Rightarrow \,\,\,2\alpha \,\, = \,\,1.5\,\,\)

\( \Rightarrow \,\,\alpha \,\, = \,\,0.75\)

\(\,\alpha (in\,\% )\,\, = \,\,75\% \)