Question

The decomposition of NH4HS is endothermic:

NH4HS(s) ⇌ NH3(g) + H2S(g)
Which change to an equilibrium mixture of this reaction results in the formation of more H2S?

-an increase in the amount of NH4HS in the reaction vessel
-removing NH3 from the reaction mixture as it forms
-a decrease in the volume of the reaction vessel (at constant temperature)
-all of the above

Answer 1

The formation of more H2S in the decomposition of NH4HS can be favored by adding more NH4HS, removing NH3, and decreasing the volume of the reaction vessel at constant temperature. Based on Le Chatelier's principle, all mentioned changes will shift the equilibrium to produce more H2S.

Step-by-step explanation:

The decomposition of NH4HS (ammonium hydrosulfide) is an endothermic reaction, meaning it absorbs heat. When looking at the effects of various changes on the reaction's equilibrium, we can apply Le Chatelier's principle, which predicts how a system at equilibrium will respond to disturbances. If more NH4HS is added to the reaction vessel, more H2S will be formed as the system shifts to remove the added reactant (solid).

Removing NH3 from the reaction mixture as it forms also shifts the equilibrium to the right, favoring the formation of more NH3 and H2S to re-establish the equilibrium constant.

A decrease in the volume of the reaction vessel (at constant temperature) will increase the pressure inside the vessel. Since the reaction produces two moles of gas from one, reducing the volume will shift the equilibrium towards the right, again increasing the formation of NH3 and H2S.

Therefore, the correct answer for which change leads to more H2S formation is: all of the above.