A-LevelChemistryEquilibriaOct/Nov 2023Paper 1 Q171 Mark
The diagram shows a gas syringe with a free-moving piston. The syringe contains gaseous hydrogen, gaseous iodine and gaseous hydrogen iodide at equilibrium. [Figure of gas syringe] H2(g) + I2(g) ⇌ 2HI(g) Three changes are listed. 1 increasing the total pressure by adding an inert gas and keeping the volume constant 2 increasing the pressure by adding more gaseous hydrogen iodide and keeping the volume constant 3 decreasing the volume by pushing the piston to the left Which changes will result in an equilibrium position at which the rate of the forward reaction has increased?
A2 only
B1 and 2
C1 and 3
D2 and 3
✓ Correct Answer
The correct answer is D: 2 and 3
📋 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.
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