\(x_{2}=\frac{p_{o}-p_{s}}{p_{o}}\)
Substitute the given values in the above equation.
\(\frac{\left(\frac{0.5}{65}\right)}{\left(\frac{158}{154}\right)}=\frac{143-p_{s}}{143}\)
After solving,
\(p_{s}=141.93 \,mm\, Hg\)
[ $\mathrm{AB}_2$ નું મોલર દળ $=200 \mathrm{~g} \mathrm{~mol}{ }^{-1}$, પાણીનું ઉત્કલનબિંદુ $=100^{\circ} \mathrm{C}, \mathrm{K}_{\mathrm{b}}$ (પાણીનો મોલલ ઉત્કલનબિંદુ ઉન્નયન અચળાંક $\left.=0.52 \mathrm{~K} \mathrm{~kg} \mathrm{~mol}^{-1}\right)$ ]