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JAMB Chemistry 1988 Question 27

Question 27

Energy Changes

Which of the following statements is TRUE?

  1. A.The dissolution of NaOH(s) in water is endothermic
  2. B.The heat of solution of NaOH(s) is positive
  3. C.The NaOH(s) gains heat from the surroundings
  4. D.The heat of solution of NaOH(s) is negative.
Show the answer and explanation

Answer: D (The heat of solution of NaOH(s) is negative.)

Explanation

Solid NaOH gets hot when it dissolves: it gives out heat, so its heat of solution is negative (exothermic).