Question

For the gaseous reaction
$N_2+3H_2\rightleftharpoons {2NH}_3$
The partial pressure of $H_2$ and $N_2$ are 0.4 and 0.8 atm respectively. The total pressure of the entire system is 2.80 atm. The equilibrium constant $K_p$ will be:

• A. 50
• B. 0.02
• C. 250
• D. 31.25

Answer 1

The correct option is A 50

$N_2+3H_2\rightleftharpoons 2N{H}_3$

Given that,

Partial pressure of $N_2=0.8atm$

Partial pressure of $H_2=0.4atm$

Total pressure $=2.8atm$

Thus, partial pressure of $N{H}_3=\text{Total pressure}-(P_{N_2}+P_{H_2})$

$P_{N{H}_3}=2.8atm-(0.8+0.4)atm=1.6atm$

$K_P=\frac{[P_{N{H}_3}{]}^2}{\left[P_{H_2}{]}^3\right[P_{N_2}]}=\frac{[1.6{]}^2}{\left[0.4{]}^3\right[0.8]}=50$