Question

A gas mixture contains $2$ moles of $A$, $3$ moles of $B$, $5$ moles of $C$ and $10$ moles of $D$. If the partial pressure of $C$ is $1.5$ atm, the total pressure in atm is:

• A. $3$
• B. $6$
• C. $9$
• D. $15$

Answer 1

Answer: (B)

$6$

Total moles of A,B,C and D are $2+3+5+10=20$ moles.

$P_C=X_C\times P_T$

Mole fraction of $X_C=\frac{5}{20}=0.25$ moles

$P_T=\frac{P_C}{X_C}=\frac{1.5}{0.25}=6atm$

Hence option B is correct.