O-LevelChemistryRates of Reaction5070/12 · Oct/Nov 2014 · Q311 Mark

Bond breaking is an endothermic process and bond making is an exothermic process. For which change is it not possible, from the equation, to deduce whether the reaction is endothermic or exothermic?

ACl2(g) → 2Cl(g)

BH2(g) + Cl2(g) → 2HCl(g)

CH2O(g) → 2H(g) + O(g)

DH(g) + Cl(g) → HCl(g)

✓ Correct answer

B: H2(g) + Cl2(g) → 2HCl(g)

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Topic: Rates of Reaction, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, Oct/Nov 2014 Paper 1 Variant 2, question 31.

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