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Thursday, 11 June 2026
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Chemistry Past Questions and Answers

Chemistry Questions

Question 71:
When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;
  • A Nitrogen and carbondioxide
  • B The rare gases
  • C Nitrogen and oxygen
  • D Nitrogen and the rare gases
  • E Nitrogen, carbondioxide and the rare gases
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Question 72:
When heat is absorbed during a chemical reaction, the reaction is said to be
  • A Thermodynamic
  • B Exothermic
  • C Isothermal
  • D Endothermic
  • E Thermostatic
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Question 73:
When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as
  • A Disintegration
  • B Polymerization
  • C Cracking
  • D Degradation
  • E Distillation
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Question 74:
The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore
  • A None of these solutions is acidic
  • B The pH of Y is made more acidic by addition of distilled water
  • C Z is the most acidic solution
  • D W is the most acidic solution
  • E X is neutral
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Question 75:
When each of the nitrates of Potassium, Magnesium and iron is heated,
  • A All the nitrates decompose to their oxides
  • B The nitrate of magnesium gives the nitrite and oxygen
  • C The nitrates of iron magnesium and iron give the oxides
  • D The nitrate of iron gives the nitrite and oxygen
  • E The nitrate of the magnesium is not decomposed
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