Question

The equilibrium $H_{2_{(}g)}+I_{2_{(}g)}\leftrightharpoons 2H{I}_{\left(g\right)}$ is not affected by the change in _________.

• A. temperature
• B. pressure
• C. heat
• D. catalyst

Answer 1

The correct option is B pressure

The following equilibrium remains unaffected by pressure change :

$H_2\left(g\right)+I_2\left(g\right)\rightleftharpoons 2HI\left(g\right)$

For this equilibrium, the total number of moles of gaseous reactants are equal to total number of moles of gaseous products or $\Delta n=2-(1+1)=0$.
Note: When catalyst is added, the value of the equilibrium constant is unaffected. But the equilibrium is quickly attained.