Question

Consider the following equilibrium system: ${SO}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\rightleftharpoons {SO}_3\left(g\right)$; set up in a cylinder fitted with a piston. Some inert gas is added and the piston is moved outwards to keep the total gaseous pressure constant. Predict which of the following is true?

• A. Addition of inert gas does not affect the equilibrium
• B. Less ${SO}_2\left(g\right)$ is produced
• C. More ${SO}_2\left(g\right)$ is produced
• D. The system moves to new equilibrium position which cannot be predicted theoritically

Answer 1

Answer: (C)

More ${SO}_2\left(g\right)$ is produced

At constant pressure, when an inert gas is added to equilibrium system, volume will increase. So, the equilibrium will shift in the direction in which the number of moles of gases increase. So, in this reaction, equilibrium will shift in backward direction and more $S{O}_2\left(g\right)$ is produced.

Answer is option $C$.