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Tuesday, 16 June 2026
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Chemistry Past Questions and Answers

Topic: Separation of mixtures and purification of chemical substances

Jamb Chemistry Questions - Separation of mixtures and purification of chemical substances

Question 116:
The substance ZnO dissolves in sodium hydroxide solution and mineral acid solution to give soluble products in each case. ZnO is therefore referred to as
  • A An allotropic oxide
  • B An amphoteric oxide
  • C A peroxide
  • D A dioxide
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Question 117:
Gunpower is made from charcoal, sulphur and potassium trioxonitrate (V) The salt in the mixture performs the function of
  • A An oxidant
  • B A reductant
  • C A solvent
  • D A catalyst
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Question 118:
Bleaching powder, CaOCI2, H2O, deteriorates on exposure to air because
  • A It loses its water of crystallization
  • B Atmospheric nitrogen displaces chlorine from it
  • C Carbon (IV) oxide of the atmosphere displaceschlorine from it
  • D Bleaching agents should be stored in solution
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Question 119:
Which of the following is NOT involved in the extraction of metals from their ores?
  • A Reduction with carbon
  • B Reduction with other metals
  • C Reduction by electrolysis
  • D Oxidation with oxidizing agents
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Question 120:
In the above set up substances X and Y are respectively
  • A Lime water copper (ll) tetraoxosulphate (lV)
  • B Potassium trioxocarbonate and alkaline pyrogallol
  • C Potassium hydroxide and alkaline pyrogallol
  • D Potassium trioxocarbonate (lV) and concentrated tetraoxosulphate (IV) acid
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