Question

3 moles of A and 2 moles of B are mixed what will be the vapour pressure if there partial pressure are 40 and 30 torr respectively

Answer 1

$We know that :</p><p>P </p><p>total</p><p> </p><p> =p </p><p>P</p><p> </p><p> +p </p><p>Q</p><p> </p><p> =p </p><p>P</p><p>0</p><p> </p><p> x </p><p>P</p><p> </p><p> +p </p><p>Q</p><p>0</p><p> </p><p> x </p><p>Q</p><p>$

$where p </p><p>P</p><p>0</p><p> </p><p> and p </p><p>Q</p><p>0</p><p> </p><p> are partial pressures of pure substances.</p><p>x </p><p>P</p><p> </p><p> and x </p><p>Q</p><p> </p><p> are mole fractions.$

$x </p><p>P</p><p> </p><p> = </p><p>5</p><p>3</p><p> </p><p> =0.6$

$x </p><p>Q</p><p> </p><p> = </p><p>5</p><p>2</p><p> </p><p> =0.4$

$hence </p><p>P </p><p>total</p><p> </p><p> =p </p><p>P</p><p>0</p><p> </p><p> x </p><p>P</p><p> </p><p> +p </p><p>Q</p><p>0</p><p> </p><p> x </p><p>Q</p><p> </p><p> =80×0.6+60×0.4=72torr$