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 1: Which of the following equations show that a reaction is in equilibrium?
  Options:
  A) ΔG < O
  B) ΔG = ΔH – TΔS
  C) ΔG > O
  D) ΔG = O
  Show Answer
  The correct answer is D .
• Question 2:

  The best treatment for a student who accidentally poured conc tetraoxosulphate(vi) on his skin in the laboratory is to wash his skin with?

  Options:
  A) with cool running water
  B) sodium hydroxide solution
  C) iodine solution
  D) sodium trioxonitrate(v) solution
  Show Answer
  The correct answer is A .
• Question 3: The pressure of 100cm³ of oxygen at 35^oC is 750mmHg. What will be the volume of gas if the pressure is reduced to 100mmHg without changing the temperature? Options:
  A) 650 cm³
  B) 850 cm³
  C) 580 cm³
  D) 750 cm³
  Show Answer
  The correct answer is D .
• Question 4: 5 block elements of the periodic table one made up of Options:
  A) groups 1, 2, 3
  B) groups 1, and 2
  C) group 3
  D) group 3 to 7
  Show Answer
  The correct answer is B .
• Question 5: The air pollutant unknown in nature is Options:
  A) NO
  B) CO
  C) HCHO
  D) DDT
  Show Answer
  The correct answer is C .
• Question 6: Which of the following will produce the greatest increase in the rate of the chemical reaction represented by the equation Na₂S₂O_3(aq) + 2HCl_(aq) → 2NaCI_(aq) + H₂O_(I) + SO_2(g) + S_(g)? Options:
  A) A decrease in temperature and an increase in the concentration of the reactants
  B) An increase in the temperature and a decrease in the cocentration of the reactants
  C) An increase in temperature and an increase in the concentration of the reactants
  D) A decrease in the temperature and a decrease in the concentration of the reactants
  Show Answer
  The correct answer is C .
• Question 7: The hydrocarbon used in the production of styrene is Options:
  A) ethyne
  B) propyne
  C) ethane
  D) ethene
  Show Answer
  The correct answer is D .
• Question 8: The general formula of an alkyl halide (which represent the halide) is? Options:
  A) C_nH_2n - ₂X
  B) C_nH_2n + ₁X
  C) C_nH_2n + ₂X
  D) C_nH_2nX
  E) C_nH_2n - 1
  Show Answer
  The correct answer is B .
• Question 9: Two organic compounds K and L were treated with a few drops of Fehling's solutions respectively . K formed a brick-red precipitate while L, remains unaffected. The compound K is an Options:
  A) alkanol
  B) alkane
  C) alkanal
  D) alkanone
  Show Answer
  The correct answer is C .
• Question 10:

  Which of the following pollutants will lead to the depletion of ozone layer?

  Options:
  A) chlorofluorocarbon
  B) carbon (ii) oxide
  C) hydrogen sulphide
  D) sulphur (iv) oxide
  Show Answer
  The correct answer is A .