Question

At a temperature of 32°C, the vapor pressure of water is 35.7 mmHg. If 28g of H2SO4 are added to 300g of H2O, what will the vapor pressure of the solution be?

Answer 1

Relative lowering of vapour pressure is given by $\dfrac{p_o-p}{p_o}=mole\ fraction \ of \ solute$

$\dfrac{35.7-p}{35.7}=$ $\dfrac{\frac{28}{98}}{\frac{28}{98}+\frac{300}{18}}=\dfrac{0.286}{0.286+16.67}=\dfrac{0.286}{16.956}$

$p=35.097mm \ Hg$