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 1891: The air around a petroleum refinery is most likely to contain? Options:
  A) CO₂, SO₃ and N₂O
  B) CO₂, CO and N₂O
  C) SO₂, CO and NO₂
  D) PH₃ H₂O and CO₂
  Show Answer
  The correct answer is C .
• Question 1892:

  What is the percentage by mass of oxygen in Al₂(SO₄)₃. 2H₂O?

  [Al = 27, S = 32, H = 1, O = 16]

  Options:
  A) 14.29%
  B) 25.39%
  C) 50.79%
  D) 59.25%
  Show Answer
  The correct answer is D .
• Question 1893: Calculate the mass, in kilograms, of magnesium produced by the electrolysis of magnesium (II) chloride in a cell operating for 24 hours at 500 amperes. Options:
  A) 2.7
  B) 5.4
  C) 10.8
  D) 21.7
  Show Answer
  The correct answer is B .
• Question 1894:

  The general formula of alkanoates is?

  Options:
  A) $RCHO$
  B) $R_{2}CO$
  C) $RCOOH$
  D) $RCOO{R}^{\prime }$
  Show Answer
  The correct answer is D .
• Question 1895: What volume of CO₂ at s.t.p would be obtained by reacting trioxocarbonate (IV) with excess acid?(G.M.V at s.t.p = 22.4 dm³) Options:
  A) 2.240 cm ³
  B) 22.40 cm ³
  C) 224.0 cm ³
  D) 2240 cm ³
  Show Answer
  The correct answer is B .
• Question 1896: 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 1897: Solutions X, Y, and Z have PH values 3.0. 5. 0 and 9. 0 respectively. Which of the following statements is correct? Options:
  A) All the solutions are acidic
  B) All the solutions are basic
  C) Y and Z are more acidic than water
  D) Y is more acidic than X
  E) Z is the least acidic
  Show Answer
  The correct answer is E .
• Question 1898: The IUPAC nomenclature of compound CH₃CH₂COOCH₂CH₃ is Options:
  A) propyl ethanoate
  B) ethyl butanoate
  C) ethyl propanoate
  D) methyl butanoate
  Show Answer
  The correct answer is C .
• Question 1899: Which of the following molecules is held together by hydrogen bond? Options:
  A) CH₄
  B) HBr
  C) H₂SO₄
  D) HF
  Show Answer
  The correct answer is D .
• Question 1900: The constituents of baking powder that makes the dough to rise is Options:
  A) NaHCO₃
  B) NaOH
  C) Na₂CO₃
  D) NaCl
  Show Answer
  The correct answer is A .