Question

A gaseous mixture of $N_2$ and gas $A$ at ${30}^{o}C$ has a total pressure of $6atm$. Contains $30mol$ percent of $N_2$. The partial pressure of $A$ is:

• A. $4.2atm$
• B. $1.8atm$
• C. $3atm$
• D. $2atm$

Answer 1

The correct option is A $4.2atm$

We have $N_2$ and $A$ in the gas mixture ,Mole fraction of $N_2$ is $0.3$(30 percent)

$X_{N_2}=0.3$

Since mole fraction of both gases add up to 1;

So

$X_A=0.7$

Total pressure $\left(P_T\right)=6atm$

Partial pressure$=$(mole fraction)$\times$(total pressure)

$P_A=X_A\times P_T$

$P_A=0.7\times 6=4.2atm$

Therefore the partial pressure of A is 4.2 atm