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Wednesday, 20 May 2026
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Chemistry Past Questions and Answers

Jamb 1978 Chemistry Questions

Question 31:
The most common type of chemical reaction which alkanes undergo is
  • A Substitution
  • B Addition
  • C Condensation
  • D Polymerisation
  • E Double decomposition
View Answer & Explanation
Question 32:
Consider the following exothermic reaction
2SO2(g) + O2(g) ↔ 2SO3(g)
If the temperature of the reaction is reduced from 800°C to 500°C, an no other change takes place, then
  • A The reaction rate increases
  • B Concentration of SO<sub style='font-size: smaller;'>3</sub> decreases
  • C Concentration of SO<sub style='font-size: smaller;'>3</sub> increases
  • D SO<sub style='font-size: smaller;'>2</sub> gas becomes unreactive
  • E O<sub style='font-size: smaller;'>3</sub> gas becomes unreactive
View Answer & Explanation
Question 33:
If excess zinc is added to a bluish green solution of copper (II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because
  • A Both zinc and copper are metals
  • B The sulphate radical and the zinc ion are divalent
  • C Zinc is more electropositive than copper
  • D Both zinc and copper form depositive ions in solution
  • E Zinc is a reducing agent
View Answer & Explanation
Question 34:
Three solutions contain carbonate, sulphate and sulphide ions respectively. One test that will identify just ONE of them completely is by addition to each of them of
  • A Barium chloride solution
  • B Dilute hydrochloric acide
  • C Lead nitrate solution
  • D Calcium chloride solution
  • E Sodium hydroxide solution
View Answer & Explanation
Question 35:
Two gas cylinders contain ethylene (ethene) and acetylene respectively. One test which can be used to distinguish between them is by
  • A Passing each gas through bromine water
  • B Passing each gas through dilute potassium permanganate solution
  • C Passing each gas through silver nitrate solution
  • D Treating each gas catalytically with excess hydrogen gas
View Answer & Explanation