Which of the following changes is endothermic? 2H₂(g) + O₂(g) → 2H₂O(l), H(g) + Cl(g) → HCl(g), H₂O(g) → 2H(g) + O₂(g), H₂O(l) → H₂O(s)

Everyday Science / Chemistry — Multiple-choice practice

درج ذیل میں سے کون سا عمل اینڈوتھرمک (حرارت جذب کرنے والا) ہے؟

  1. A. 2H₂(g) + O₂(g) → 2H₂O(l)
  2. B. H(g) + Cl(g) → HCl(g)
  3. C. H₂O(g) → 2H(g) + O₂(g)
  4. D. H₂O(l) → H₂O(s)

Correct answer

H₂O(g) → 2H(g) + O₂(g)

Explanation

Explanation H₂O(g) → 2H(g) + O₂(g) Endothermic reactions absorb heat from the surroundings. Breaking bonds requires energy input. Water vapour (H₂O) is broken into atoms, which needs energy. Therefore, this process is endothermic . Last verified on 11-04-2026

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