Question

At $40^{\circ }C$ , the vapour pressures in torr, of methyl alcohol and ethyl alcohol solutions is represented by the equation $P=119X_A+135$ where $X_A$ is mole fraction of methyl alcohol, then the value of $\underset{x_A\to 1}{\lim }\frac{P_A}{X_A}$ is

• A. $254$ torr
• B. $135$ torr
• C. $119$ torr
• D. $140$ torr

Answer 1

Answer: (A)

$P=119X_A+135$
$\underset{x_A\to 1}{\lim }\frac{P_A}{X_A}=119+135=254$ torr (Put $X_A=1$ )