Question

In which of the following equilibrium, equilibrium can not be identified by observing variation in pressure?

• A. Decomposition of $HI$
• B. Decomposition of $CaC{O}_3$
• C. Decomposition of $N{H}_{4}HS$
• D. None of the above

Answer 1

Answer: (A)

Decomposition of $CaC{O}_3$ and $N{H}_{4}HS$ involve formation of gaseous products, the equilibrium can be recognised by observing constancy of pressure. Only decomposition of HI does not involve any change in pressure during the reaction and hence cannot be recognised by observing pressure (as $\Delta n=0$ ).