# A binary solution contains 4 mol of A and 6 mol of B.Its vapour pressure is found to be 460mm Hg.To this solution,when 10 mol of B is added,its vapour pressure becomes 480mm Hg.The vapour pressures of pure A and pure B,respectively,are

$\begin{array}{1 1}\text{300 mmHg,600 mmHg}\\\text{400 mmHg and 500 mmHg}\\\text{300 mmHg,500 mmHg}\\\text{400 mmHg and 600 mmHg}\end{array}$

Answer : 400 mmHg and 500mmHg
Initially,mole fractions of A and B in liquid solutions are 0.4 and 0.6 respectively.The addition of 10 mol of B changes mole fraction to 0.2 and 0.8 respectively.With these mole fractions,$p_A^*$ and $p_B^*$ are 400mmHg and 500mmHg respectively.