Question

If the pressure of $N_2$ and $H_2$ mixture in a closed apparatus is $100atm$ and $20$ of the mixture then reacts, the pressure at the same temperature would be:

• A. $100$
• B. $90$
• C. $85$
• D. $80$

Answer 1

Answer: (A)

$100$

Let there be $1mole$ of $N_2$ and $3mole$ of $H_2$.

So, $P_{N_2}=25atm;P_{H_2}=75atm$

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

$25(1-0.2)$ $75(1-0.2)$ $50\times 0.2$

$20$ $60$ $20$

Total pressure $=20+60+20=100atm$