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?

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

Answer 1

To shift the equilibrium for the endothermic decomposition of NH4HS and form more H2S, you can increase the amount of NH4HS, remove NH3 as it forms, or decrease the volume of the reaction vessel; although the latter doesn't affect equilibrium in this particular case.

Step-by-step explanation:

The decomposition of NH4HS is endothermic, and the equilibrium can be affected by changes in the system. There are several ways to shift the equilibrium to form more H2S:

• Decreasing the volume of the reaction vessel (at a constant temperature) will increase the pressure, and the equilibrium will shift towards the side with fewer moles of gas to reduce the pressure. However, since the reaction produces equal moles of NH3 and H2S, the change in volume does not affect the equilibrium in this case.
• Increasing the amount of NH4HS in the reaction vessel will shift the equilibrium towards the products to consume the added reactant, thus producing more H2S.
• Removing NH3 from the reaction mixture as it forms will also shift the equilibrium towards the products to replace the removed NH3, leading to more production of H2S.

Hence, all of the above changes to the system would result in the formation of more H2S.