Question

$N_2+3H_2\rightleftharpoons 2N{H}_3$, starting with one mole of nitrogen and 3 moles of hydrogen, at equilibrium 50% of each had reacted. If the equilibrium pressure is $P$, the partial pressure of hydrogen at equilibrium would be:

• A. $\frac{P}{2}$
• B. $\frac{P}{3}$
• C. $\frac{P}{4}$
• D. $\frac{P}{6}$

Answer 1

The correct option is A $\frac{P}{2}$

The given reaction is $N_2+3H_2\rightleftharpoons 2N{H}_{3}130...\text{initial}0.51.51...\text{at equilibrium}$
According to Dalton's law of partial pressure
$P_i=X_i{P}_i^o$
$X_{H_2}=\frac{1.5}{3}$
Now partial pressure of $H_2$,
$P_{H_2}=\frac{1.5}{3}P=\frac{P}{2}$
Hence, correct option is a.