An aq. solution containing 64% by weight of volatile liquid ‘A’ (molecular mass 128) has pressure of 145mm, then vapour pressure of ‘A’ is (Vapour Pressure of $H_{2}O$ is 155 mm)

Given data:It is given to identify vapour pressure of of A in aqueous solution.

Explanation:

$$\begin{gathered} Raoult\text{'}s law for liquid mixtures states. \\ P=P_A^{\circ }\times \frac{\frac{W_A}{M_A}}{\frac{W_A}{M_A}\times \frac{W_B}{M_B}}+P_B^{\circ }\times \frac{\frac{W_B}{M_B}}{\frac{W_A}{M_A}+\frac{W_B}{M_B}} \\ P=145=P_A^{\circ }\times \frac{\frac{64}{128}}{\frac{64}{128}+\frac{36}{18}}+155\times \frac{\frac{36}{18}}{\frac{64}{128}+\frac{36}{18}} \\ {P}_A^{\circ }=105mm \end{gathered}$$

Hence, the correct option is: (C) 105mm