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 981: The uncovered raw food that is sold along major roads is likely to contain some amounts of Options:
  A) Pb
  B) Cu
  C) Ag
  D) Na
  Show Answer
  The correct answer is A .
• Question 982: The final products of the reaction between methane and chlorine in the presence of ultraviolet light are hydrogen chloride and Options:
  A) tricloromethane
  B) dichloromethane
  C) tetrachloromethane
  D) chloromethane
  Show Answer
  The correct answer is C .
• Question 983: Bleaching powder, CaOCI₂, H₂O, deteriorates on exposure to air because Options:
  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
  Show Answer
  The correct answer is C .
• Question 984: The number of isomers formed by C₆H₁₄ is Options:
  A) 4
  B) 5
  C) 2
  D) 3
  Show Answer
  The correct answer is B .
• Question 985: An aqueous solution of an inorganic salt gave white precipitate (i) soluble in excess aqueous NaOH (ii) insoluble in excess aqueous NH₃ (iii) with dilute HCl. The cation present in the inorganic salt is? Options:
  A) Na₄⁺
  B) Ca⁺⁺
  C) Zn⁺⁺
  D) Al⁺⁺⁺
  E) Pb₊₊
  Show Answer
  The correct answer is E .
• Question 986:

  What volume of oxygen is produced from the decomposition of 2 mole of KCIO₃ at s.t.p?

  [Molar volume of a gas at s.t.p = 22.4 dm³]

  Options:
  A) 22.4 dm³
  B) 33.6 dm³
  C) 44.8 dm³
  D) 67.2 dm³
  Show Answer
  The correct answer is D .
• Question 987: Which of the following is a property of ionic chlorides? Options:
  A) They can be decomposed by heat
  B) They react with aqueous AgNO₃ to give a white precipiate which is soluble in excess ammonia
  C) They explode when in contact with dry ammonia
  D) They react with concentrated tetraoxosulphate (IV) acid to give white fumes of chlorine gas
  Show Answer
  The correct answer is B .
• Question 988: which of these metals CANNOT replace hydrogen from alkaline solutions? Options:
  A) Aluminium
  B) Zinc
  C) Tin
  D) Iron
  Show Answer
  The correct answer is A .
• Question 989: The characteristic colour of the flame shown when a copper sail moistened with concentrated hydrochloric acid on a platinum wire is put on bunsen burner is Options:
  A) lilac
  B) green
  C) yellow
  D) brick-red
  Show Answer
  The correct answer is B .
• Question 990: In two separate experiments, 0.36g and 0.71g of chlorine combined with a metal X to give Y and Z respectively. An analysis showed that Y and Z contain 0.20g and 0.40g of X respectively. The data above represents the law of ? Options:
  A) multiple proportion
  B) conservation of mass
  C) constant composition
  D) reciprocal proportion
  Show Answer
  The correct answer is C .