Chemistry 9701 · AS & A Level · Equilibria

Equilibria — practice question

Ammonia gas, $\text{NH}_3$, together with hydrogen sulfide gas, $\text{H}_2\text{S}$, combine to make the salt ammonium sulfide, $(\text{NH}_4)_2\text{S}$. When ammonium sulfide is dissolved in water, it gives an orange alkaline solution. $(\text{NH}_4)_2\text{S(aq)} \rightleftharpoons \text{NH}_3\text{(aq)} + \text{NH}_4\text{SH(aq)}$ If $\text{NaOH(aq)}$ is added to this solution, a gas, X, is formed. If $\text{HCl(aq)}$ is added to another sample of the solution, a gas, Y, is formed. X and Y may be different gases, or they may be the same gas. What are the identities of X and Y?

  • AX: $\text{H}_2\text{S}$, Y: $\text{H}_2\text{S}$
  • BX: $\text{H}_2\text{S}$, Y: $\text{NH}_3$
  • CX: $\text{NH}_3$, Y: $\text{H}_2\text{S}$
  • DX: $\text{NH}_3$, Y: $\text{NH}_3$

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