Question

One mole of $N_2{O}_5\left(g\right)$ at 300 K is left in a closed container under one atm. It is heated to 600 K when 20% by mass of $N_2{O}_5\left(g\right)$ decomposes to $N{O}_2\left(g\right)$. The resultant pressure is:

• A. 1.2 atm
• B. 2.4 atm
• C. 2.0 atm
• D. 1.0 atm

Answer 1

The correct option is B 2.4 atm

Assuming there to be present 1 mole of $N_2{O}_5$.

On reaching equilibrium, we have,

$N_2{O}_5\rightleftharpoons 2N{O}_2$,

$1(1-0.2)$ $2\times 0.2$

Hence, the total number of moles present is 1.2.

Now, using the ideal gas law, PV=nRT,

For a closed vessel, the volume is constant.

Hence, $\frac{1\times 300}{1}=\frac{1.2\times 600}{P}$

$\therefore$, P = 2.4 atm.

Hence, the correct option is $\text{B}$