Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 1021: If an equilibrium reaction has ΔH > 0, the reaction will proceed favourably in the forward direction at Options:
  A) High temperature
  B) Any temperature
  C) Low temperature
  D) Minimum temperature
  Show Answer
  The correct answer is A .
• Question 1022: The air pollutant unknown in nature is Options:
  A) NO
  B) CO
  C) HCHO
  D) DDT
  Show Answer
  The correct answer is D .
• Question 1023: The ion that can be used as an oxidizing agent is Options:
  A) Au³⁺
  B) Fe³⁺
  C) F^-
  D) Ca²⁺
  Show Answer
  The correct answer is C .
• Question 1024: 9.8g of solid potassium chlorate (KCIO₃) were added to 40 cm³ of water and heated to dissolve all the solid. As he solution cooled, crystals of potassium chlorate started forming at 60°C. The solubility of potassium chlorate at 66°C is therefore? Options:
  A) 24.5 mole per dm³
  B) 0.2 mole per dm³
  C) 10.0 mole per dm³
  D) 20.0 mole per dm³
  E) 2.0 mole per dm³
  Show Answer
  The correct answer is E .
• Question 1025: Due to the unstable nature of ethyne, it is stored by dissolving in Options:
  A) ethane-1,2-diol
  B) propanol
  C) ethanoic acid
  D) propanone
  Show Answer
  The correct answer is D .
• Question 1026: The noble gas, argon, is used for Options:
  A) electrical arc welding
  B) welding brass
  C) underwater welding
  D) steel-welding
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  The correct answer is A .
• Question 1027:

  The combustion of carbon(ii)oxide in oxygen can be represented by equation.

  2CO + O${}_2$ → 2CO${}_2$

  Calculate the volume of the resulting mixture at the end of the reaction if 50cm${}_3$ of carbon(ii)oxide was exploded in 100cm${}_3$ of oxygen

  Options:
  A) 75cm${}^3$
  B) 125cm${}^3$
  C) 100cm${}^3$
  D) 50cm${}^3$
  Show Answer
  The correct answer is B .
• Question 1028: The function of conc. H₂SO₄ in the esterification of ethanoic acid with ethanol is to Options:
  A) serve as a dehydrating agent
  B) serve as a solvent
  C) act as a catalyst
  D) prevent any side reaction
  E) serve as an oxidizing agent
  Show Answer
  The correct answer is C .
• Question 1029: The solution with the lowest pH value is Options:
  A) 5 ml of (m/10) HCL
  B) 10 ml of (m/10) HCL
  C) 15 ml of (m/5) HCL
  D) 20 ml of (m/8) HCL
  Show Answer
  The correct answer is A .
• Question 1030:

  Which of the following mixtures is an example of a colloid?

  Options:
  A) Milk
  B) Orange juice
  C) Saltwater
  D) Sugar dissolved in water
  Show Answer
  The correct answer is A .