The vapour pressure of heptane and toluene at `50^@C` are 141 mm and 93 mm respectively. Find the composition of the solution (containing toluene and heptane) at which the partial pressure of toluene is equal to that of heptane.

Explanation

To solve the problem, we need to find the composition of a solution of heptane and toluene at which the partial pressures of both components are equal. We will use Raoult's Law to achieve this.

### Step-by-Step Solution:

1. **Understand Raoult's Law**:
According to Raoult's Law, the partial pressure of a component in a solution is equal to the vapor pressure of the pure component multiplied by its mole fraction in the solution.
\[
P_A = P^0_A \cdot X_A
...