QJEEM16Ch73e8: JEE Main 2016 Chemistry - Class 12 JEEM16Ch73e8 Solution: 18 g glucose (C 6 H 12 O 6 ) is added to 178.2 g water. The…

According to Raoult's Law

${{{P^ \circ } - {P_s}} \over {{P_s}}} = {{{W_B} \times {M_A}} \over {{M_B} \times {W_A}}}\,\,\,\,\,\,\,\,\,\,...\left( i \right)$

Here ${P^ \circ } =$ Vapour pressure of pure solvent,

${P_s} =$ Vapour pressure of solution

${W_B} =$ Mass of solute,

${W_A} =$ Mass of solvent

${M_B} =$ Molar mass of solute,

${M_A} =$ Molar Mass of solvent

Vapour pressure of pure water at ${100^ \circ }C$

(by assumption $=760$ torr)

By substituting values in equation $(i)$ we get,

${{760 - {P_s}} \over {{P_s}}} = {{18 \times 18} \over {180 \times 178.2}}\,\,\,\,\,\,...\left( {ii} \right)$

On solving $(ii)$ we get

On solving $(ii)$ we get

${P_s} = 752.4\,\,torr$