A-LevelChemistryEquilibriaMay/June 2021Paper 1 Q331 Mark
When a sample of ammonium chloride is warmed it decomposes into ammonia and hydrogen chloride gas. NH₄Cl(s) → NH₃(g) + HCl(g) reaction 1 [Diagram of apparatus showing NH₄Cl decomposition and reformation] When the mixture of hot ammonia and hydrogen chloride gases hit a cold surface, a white solid of ammonium chloride reforms. Which statements are correct? 1 Reaction 1 is in dynamic equilibrium. 2 Reaction 1 is reversible. 3 Reaction 1 is an endothermic reaction.
A1, 2 and 3 are correct
B1 and 2 only are correct
C2 and 3 only are correct
D1 only is correct
✓ Correct Answer
The correct answer is C: 2 and 3 only are correct
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
🔒
Unlock the Examiner's Analysis
Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep