CBSE 2025 · Region 4 · Set 2 · Q17 · 1 mark
Assertion (A) : All exothermic reactions are accompanied with evolution of heat and light.
Reason (R) : Combination reactions may or may not be exothermic.
Official answer
From CBSE’s own marking scheme for this paper.
(D)
Assertion (A) is false, but Reason (R) is true.
Chemical Reactions and EquationsCombination and Decomposition ReactionsAnalyseassertion_reasonmedium
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CBSE Class 10 Science past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.