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Sunday, 14 June 2026
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Chemistry Past Questions and Answers

Waec Chemistry Questions

Question 1451:
Consider the following equilibrium reaction: \(2AB_{{2}{(g)}} + B_{{2}{(g)}} \to 2AB_{{3}{(g)}}\). \(\Delta H= -X kJmol^{-1}\). The backward reaction will be favored by
  • A A decrease in pressure
  • B An increase in pressure
  • C A decrease in temperature
  • D An introduction of a positive catalyst
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Question 1452:
What is the mass of solute in 500\(cm^{3}\) of 0.005\(moldm^{-3}\) \(H_{2}SO_{4}\)? ( H = 1, S = 32.0, O=16.0)
  • A 0.490g
  • B 0.049g
  • C 0.245g
  • D 0.0245g
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Question 1453:
Pure water can be made to boil at a temperature lower than 100°C by
  • A Reducing its quantity
  • B Decreasing the external pressure
  • C Distilling it
  • D Increasing the external pressure
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Question 1454:
At what temperature does the solubility of \(KNO_{3}\) equal that of \(NaNO_{3}\)?
  • A 0°C
  • B 20°C
  • C 30°C
  • D 40°C
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Question 1455:
When a salt is added to its saturated solution, the salt
  • A Dissolves and the solution becomes super saturated
  • B Dissolves and the solution becomes unsaturated
  • C Precipitates and the solution remains unchanged
  • D Dissolves and crystals are formed
View Answer & Explanation