Question

At ${40}^{o}c$ the vapour pressures in torr, of methyl alcohol-ethyl alcohol solutions is represented by the equation. $P=119X_A+135$; whereas, $X_A$ 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)

$254$ torr

The value of $\underset{X_{A\to 1}}{lim}\frac{P_A}{X_A}$ will be $254torr$
$P=119X_A+135$
$\underset{X_{A\to 1}}{lim}\frac{P_A}{X_A}=119+135=254torr$.