Multiple choice

The vapour pressure of the solution of two liquids $A(p^o = 80 mm)$ and $B(p^o = 120 mm)$ is found to be 100 mm when $x_A = 0.4$. The result shows that:

  1. solution exhibits ideal behaviour

  2. solution shows positive deviations

  3. solution shows negative deviations

  4. solution will show positive deviations for lower concentration and negative deviations for higher concentrations.
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AI explanation

For an ideal solution obeying Raoult's law, the total vapour pressure is calculated as the sum of the products of each liquid's mole fraction and its pure vapour pressure. The total pressure would be (0.4 times 80) plus (0.6 times 120), which equals 32 + 72 = 100 mm. Since the calculated ideal pressure of 100 mm exactly matches the observed pressure of 100 mm, the solution exhibits ideal behaviour. The result is that the solution exhibits ideal behaviour.

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