A-LevelChemistryGroup 17Feb/Mar 2021Paper 1 Q161 Mark
Chlorine gas is reacted with aqueous sodium hydroxide. The oxidation number of chlorine changes from 0 to –1 and also from 0 to +1. Under which conditions does this reaction occur and what is the colour of the solid silver salt with chlorine in the oxidation state –1? reaction conditions colour of silver salt A cold, dilute alkali white B cold, dilute alkali yellow C hot, concentrated alkali white D hot, concentrated alkali yellow
Acold, dilute alkali, white
Bcold, dilute alkali, yellow
Chot, concentrated alkali, white
Dhot, concentrated alkali, yellow
✓ Correct Answer
The correct answer is A: cold, dilute alkali, white
📋 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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