A-LevelChemistryEquilibriaMay/June 2016Paper 1 Q151 Mark
Ammonia gas, NH₃, and hydrogen sulfide gas, H₂S, react together to form the salt ammonium sulfide, (NH₄)₂S. Ammonium sulfide dissolves in water to produce an orange alkaline solution. (NH₄)₂S(aq) ⇌ NH₃(aq) + NH₄SH(aq) The addition of NaOH(aq) to this solution produces a gas, X. The addition of HCl(aq) to a separate portion of this solution produces a gas, Y. What are the identities of X and Y? X Y H₂S H₂S H₂S NH₃ NH₃ H₂S NH₃ NH₃
AH₂S H₂S
BH₂S NH₃
CNH₃ H₂S
DNH₃ NH₃
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The correct answer is C. This question tests the candidate's understanding of equilibria within the Chemistrysyllabus. The examiner's mark scheme requires...
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