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 1711: The purest from of iron which contains only about 0.1% carbon is Options:
  A) pig iron
  B) wrough iron
  C) cast iron
  D) iron pyrite
  Show Answer
  The correct answer is B .
• Question 1712: Which of the following will produce a solution with pH less than 7 at equivalent point? Options:
  A) HNO ₃ +NaOH
  B) H ₂SO ₄ + KOH
  C) HC +Mg (OH) ₂
  D) HNO ₃ + KOH
  Show Answer
  The correct answer is C .
• Question 1713: When ammonium, potassium and calcium carbonates are each separately heated Options:
  A) none of them will decompose
  B) each of them will decompose to give carbondioxide and the respective oxide
  C) ammonium carbonate and potassium carbonate will not decompose
  D) only ammonium carbonate and the respective oxide
  E) ammonium carbonate will decompose to give carbondioxide, water and ammonia
  Show Answer
  The correct answer is D .
• Question 1714: A given mass of gas occupies 2 dm³ at 300k. At what temperature will its volume be doubled keeping the pressure constant? Options:
  A) 400k
  B) 480k
  C) 550k
  D) 600k
  Show Answer
  The correct answer is D .
• Question 1715: X is a crystalline salt of sodium solution of X in water turns litmus red and produces a gas which turns lime water milky when added to sodium carbonate. With barium chloride solution, X gives hydrochloric acid. X is Options:
  A) Na ₂CO ₃
  B) NaHCO ₃
  C) NaHSO ₄
  D) Na ₂SO ₄
  Show Answer
  The correct answer is C .
• Question 1716: Which of the following gives a precipitate when treated with NaOH solution? Options:
  A) AlCl₃
  B) NH₄CL
  C) CH₃COONa
  D) Na₂CO₃
  Show Answer
  The correct answer is A .
• Question 1717: The type of iron that is best suited for welding, making nails, chains and iron rods is Options:
  A) pig iron
  B) wrought iron
  C) cast iron
  D) iron pyrites
  Show Answer
  The correct answer is B .
• Question 1718:

  HCL_(aq) + H₂O_(l) H₃O⁺_(aq) + Cl^-_(aq)

  In the reaction above, Cl^-_(aq) is the

  Options:
  A) conjugate acid
  B) acid
  C) conjugate base
  D) base
  Show Answer
  The correct answer is C .
• Question 1719: What mass of a divalent metal M (atomic mass = 40) would react with excess hydrogen gas measured at S.T.P? Options:
  A) 8.0 g
  B) 4.0 g
  C) 0.8 g
  D) 0.4 g
  Show Answer
  The correct answer is D .
• Question 1720: Synthetic rubber obtained by the polymerization of chlorobutadiene in the presence of sodium is called? Options:
  A) teflon
  B) isoprene
  C) polythene
  D) neoprene
  Show Answer
  The correct answer is D .