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JAMB Chemistry 1984 Question 17

Question 17

Energy Changes

In dilute solution the heat of the reaction NaOH + HCl = NaCl + H2O is −57.3 kJ. Therefore the heat of the reaction 2NaOH + H2SO4 → Na2SO4 + 2H2O is

  1. A.+28.65 kJ
  2. B.−28.65 kJ
  3. C.+57.3 kJ
  4. D.−114.6 kJ
  5. E.−229.2 kJ
Show the answer and explanation

Answer: D (−114.6 kJ)

Explanation

−57.3 kJ is released for each mole of water formed in neutralisation. This reaction forms 2 moles of water, so the heat is 2 × (−57.3) = −114.6 kJ.