Consider the following reaction in a closed system:

Question

H_2(g) + I_2(g) → 2HI_(g)

Which of the following will decrease the rate of the reaction?

A. 

add some H₂

B. 

remove some HI

C. 

increase the volume

D. 

increase the temperature

Answer 1

Consider that all species in the reaction are in the gaseous phase.

Rate of reaction is dependent on concentration, particle size, temperature, etc.

A. adding some H2 will increase the rate because you are increasing the [H2] reactant.

B. removing some HI will shift equilibrium to the right, but will not increase the rate of reaction

C. Increase the volume will decrease the concentrations and will not increase the rate of reaction

D. Increase the temperature may increase the rate of reaction if the reaction is endothermic.

So, likely answers would be A and D