A-LevelChemistryGroup 17Oct/Nov 2025Paper 1 Q221 Mark
X and Y are sodium salts of Group 17 elements. When X reacts with concentrated sulfuric acid, hydrogen sulfide, H2S, is produced. When Y reacts with concentrated sulfuric acid, there is no change in the oxidation number of the sulfur. Which statement is correct?
AAqueous X reduces aqueous bromine.
BAqueous Y reacts with aqueous silver nitrate to give a precipitate which is insoluble in concentrated aqueous ammonia.
CX and Y react separately with concentrated sulfuric acid to produce halogens.
DWhen X reacts with concentrated sulfuric acid, six halide ions are needed to reduce one sulfur atom to H2S.
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The correct answer is A. This question tests the candidate's understanding of group 17 within the Chemistrysyllabus. The examiner's mark scheme requires...
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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...
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