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 361: The acid used in electrolysis of water is dilute Options:
  A) HNO₃
  B) CH₃COOH
  C) H₂SO₄
  D) HCl
  Show Answer
  The correct answer is C .
• Question 362: Hydration of ions in solution is associated with Options:
  A) absorption of heat
  B) reduction of heat
  C) conduction of heat
  D) liberation of heat
  Show Answer
  The correct answer is D .
• Question 363: Which of the following combination of gases is used for metal welding? i. Oxygen and ethyne, ii. Hydrogen and ethyne, iii. Hydrogen and oxygen, iv. Ethyne, hydrogen and oxygen. Options:
  A) i and ii
  B) ii and iv
  C) i and iii
  D) ii and iv
  Show Answer
  The correct answer is A .
• Question 364: An electron can be added to a halogen atom to form a halide ion with Options:
  A) 2 valence electrons
  B) 3 valence electrons
  C) 7 valence electrons
  D) 8 valence electrons
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  The correct answer is D .
• Question 365: Which of the following statement is true of a proton? Options:
  A) The mass of a proton is 1840 times the mass of electron
  B) the total mass of the protons in a particular nucleus is always half the nuclear size
  C) The mass of a proton is one - twelfth the molar mass of carbon
  D) The mass of a proton is 1.0008g
  Show Answer
  The correct answer is D .
• Question 366: The temperature of a body decreases when drops of liquid placed on it evaporate because? Options:
  A) the atmospheric vapour pressure has a cooling effect on the body
  B) a temperature gradient exists between the drops of liquid and the body causing the latter to vaporate
  C) the heat of vapourization is drawn from the body causing it to cool
  D) the random motion of the liquid molecules causes a cooling effect on the body
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  The correct answer is C .
• Question 367: A liquid begins to boil when? Options:
  A) its vapour pressure is equal to the vapour pressure of its solid at the given temperature
  B) molecules start escaping from its surface
  C) its vapour pressure equals the atmosphere pressure
  D) its volume is sightly increased
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  The correct answer is C .
• Question 368: The set of pollutants that is most likely to be produced when petrol is accidentally spilled on plastic materials and ignited is Options:
  A) CO, CO² and SO²
  B) CO, HCL and SO²
  C) CO, CO² and HCL
  D) SO², CO² and HCL
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  The correct answer is B .
• Question 369: Detergents are manufactured with straight hydrocarbon chains so as to make them Options:
  A) soluble
  B) biodegradable
  C) cheaper
  D) foamy
  Show Answer
  The correct answer is B .
• Question 370: If hydrogen sulphide gas is passed into a solution of a pure iron chloride, a yellow deposit appears. If the deposit is filtered, a pale green solution is left behind. The pale green solution is Options:
  A) dilute sulphuric acid
  B) dilute hydrochloric acid
  C) unreacted hydrogen sulphide in water
  D) iron (III) chloride
  E) Iron (II) chloride
  Show Answer
  The correct answer is E .