(નજીકનાં પૂર્ણાંકમાં રાઉન્ડ ઑફ) $\left[ K _{ b }=0.52 \,K \,kg \,mol ^{-1}\right]$
$i =1-\alpha+ n \alpha=1-0.75+2 \times 0.75=1.75$
$\Delta T _{ b }= ik _{ b } m$
or, $2.5=1.75 \times 0.52 \times m$
or, $m =\frac{2.5}{1.75 \times 0.52}=2.74$
$\therefore$ nearest integer answer will be $3$
$(i)$ $0.10\, {M} \,{Ba}_{3}\left({PO}_{4}\right)_{2}$
$(ii)$ $0.10\, {M}\, {Na}_{2} {SO}_{4}$
$(iii)$ $0.10\, {M}\, {KCl}$
$(iv)$ $0.10 \,{M} \,{Li}_{3} {PO}_{4}$