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 1991:

  A current of 10.0A was passed for 1 hour through a solution of copper (ll) sulphate between the copper electrodes. Which of the following observation would be correct?

  (1 Faraday = 96,500 coulobms) (i) 0.186 mole of copper is dissolved from the anode. (ii) 0.372 mole of copper is deposited on the cathode. (iii) the original Cu²⁺ ion concentration of the solution remains unchanged. (iv) the original Cu²⁺ ion concentration of the solution decreases.

  Options:
  A) i and ii
  B) i and iii
  C) i and iv
  D) ii and iii
  E) ii and iv
  Show Answer
  The correct answer is B .
• Question 1992: Which of these solutions will give a white precipitate with a solution of barium chloride acidified with hydrochloric acid? Options:
  A) Sodium trioxocarbonate (IV)
  B) Sodium tetraoxosulphate (IV)
  C) Sodium trioxosulphate (IV)
  D) Sodium sulphide
  Show Answer
  The correct answer is A .
• Question 1993: The number of electronic shells contained in an atom with electron configuration 1s²2s²2p⁶3s²3p⁶4s² is Options:
  A) 3
  B) 2
  C) 4
  D) 5
  Show Answer
  The correct answer is C .
• Question 1994:

  

  The compound above is

  Options:
  A) glycol
  B) primary alkanol
  C) secondary alkanol
  D) tertiary alkanol
  Show Answer
  The correct answer is C .
• Question 1995:

  Which of the following is a characteristic property of acids?

  Options:
  A) Turn litmus paper blue
  B) Bitter taste
  C) pH value above 7
  D) React with metals to produce hydrogen gas
  Show Answer
  The correct answer is D .
• Question 1996:

  A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).

  Compound X is?

  Options:
  A) an alkene
  B) an alkane
  C) an alkyne
  D) tetrachloromethane
  E) dichloromethane
  Show Answer
  The correct answer is B .
• Question 1997: Which of the following statements is an exception in the assumptions of the kinetic theory of gases? Options:
  A) Gases are composed of many elastic particles
  B) The particles are of negligible size
  C) The particles are in constant random motion
  D) The particles are of negligible mass
  E) The particles collide with each other
  Show Answer
  The correct answer is D .
• Question 1998: Calculate the volume of 0.5 mol dm^-3 H₂So₄ that is neutralized by 25 cm³ of 0.1 mol dm^-3 NaOH Options:
  A) 5.0 cm³
  B) 2.5 cm³
  C) 0.4 cm³
  D) 0.1 cm³
  Show Answer
  The correct answer is B .
• Question 1999: Alkanals can be distinguished from alkanones by the reaction with Options:
  A) sudan lll stain
  B) starch iodide paper
  C) lithium tetrahydrido aluminate (lll)
  D) fehling's solution
  Show Answer
  The correct answer is D .
• Question 2000:

  

  In the diagram above , the activation energy for the backward reaction is

  Options:
  A) +5kJ
  B) +15KJ
  C) +25KJ
  D) +30KJ
  Show Answer
  The correct answer is C .