A-LevelChemistryReaction kinetics9701/12 · Oct/Nov 2013 · Q51 Mark

An autocatalytic reaction is a reaction in which one of the products catalyses the reaction. Which curve was obtained if the rate of reaction was plotted against time for an autocatalytic reaction?

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AGraph showing rate starting at zero, increasing, then levelling off.

BGraph showing rate starting at zero, increasing, then decreasing to a non-zero constant rate.

CGraph showing rate starting at zero, increasing to a maximum, then decreasing towards zero.

DGraph showing rate starting at a high value, decreasing, then levelling off at a non-zero constant rate.

✓ Correct answer

C: Graph showing rate starting at zero, increasing to a maximum, then decreasing towards zero.

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Topic: Reaction kinetics, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, Oct/Nov 2013 Paper 1 Variant 2, question 5.

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