Question

The reaction $N _{2} O _{5}( g ) \rightleftharpoons 2 NO _{2}( g )+\frac{1}{2} O _{2}( g )$ is started with initial pressure of $N _{2} O _{5}( g )$ equal to $600$ torr. What fraction of $N _{2} O _{5}$ (g) decomposed when total pressure of the system is $960$ torr?

• A. $0.05$
• B. $0.1$
• C. $0.2$
• D. $0.4$

Answer 1

Answer: (D)

At equilibrium:
Total press is $\left(600+\frac{3 p}{2}\right)$ torr
$\therefore 600+\frac{3 p}{2}=960 $
or $ \frac{3 p}{2}=360 $
or $p=240$ torr
$\therefore$ Fraction of $N _{2} O _{5}( g )$ decomposed $=\frac{240}{600}=0.4$