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:

  6AgNO_4(aq) + PH_3(g) + 3H₂O_(l) → 6Ag_(s) + H₃PO_3(g) + 6HNO_3(aq)

  In the above reaction, the reducing agent is

  Options:
  A) HNO_3(aq)
  B) H₂O_(l)
  C) PH_3(g)
  D) AgNO_3(aq)
  Show Answer
  The correct answer is C .
• Question 2: In the course of an experiment, two gases X and Y were produced. X turned wet lead ethanoate to black and Y bleached moist litmus paper. What are the element(s) in each of the gases X and Y respectively? Options:
  A) H and S;Cl
  B) H and O;Cl
  C) H and S;C and O
  D) H and Cl;S and O
  Show Answer
  The correct answer is A .
• Question 3:

  An organic compound which decolorizes bromine water is likely to be?

  Options:
  A) C${}_3$H${}_8$
  B) C${}_2$H${}_6$
  C) C${}_4$H${}_{1}0$
  D) C${}_2$H${}_4$
  Show Answer
  The correct answer is D .
• Question 4: If the ONLY pollutants found in the atmosphere over a city are oxides of nitrogen, suspended lead compounds. carbon monoxide and high levels of methane, the probable source(s) of the pollution must be? Options:
  A) automobile exhaust and biological decomposition
  B) combustion of coal and automobile exhaust
  C) biological decomposition only
  D) combustion of coal, automobile exhaust and biological decomposition
  E) combustion of coal and biological decomposition
  Show Answer
  The correct answer is B .
• Question 5: A mixture of 0.20 mole of Ar, 0.20 mole of N₂ and 0.30 mole of He exerts a total pressure of 2.1 atm. The partial pressure of He in the mixture is? Options:
  A) 0.90 atm
  B) 0.80 atm
  C) 0.70 atm
  D) 0.60 atm
  Show Answer
  The correct answer is A .
• Question 6:

  C_(s) + H₂O_(g) → H_2(g) + CO_2(g)

  ΔG for the reaction above at 1300k is -43KJ. At this temperature, the reaction is

  Options:
  A) not feasible
  B) at equilibrium
  C) feasible
  D) exothermic
  Show Answer
  The correct answer is C .
• Question 7: Dynamic equilibrium describes a situation where Options:
  A) a reaction gives back the reactant
  B) te concentration of the reactant and products is equal
  C) both forward and and reverse reactions proceed at the same rate
  D) reactants are converted to products
  Show Answer
  The correct answer is C .
• Question 8: The property which makes alcohol soluble in water is the Options:
  A) boiling point
  B) hydrogen bonding
  C) ionic character
  D) covalent nature
  Show Answer
  The correct answer is B .
• Question 9: Which of these metals, Mg, Fe, Pb and Cu will dissolve in dilute HCI? Options:
  A) All the metals
  B) Mg ,Fe and Cu
  C) Mg, Fe and Pb
  D) Mg and Fe only
  E) Mg only
  Show Answer
  The correct answer is D .
• Question 10: Smog usually occurs over cities which Options:
  A) burn a lot of fossil fuels
  B) have very few plants
  C) are surrounded by water
  D) are overpopulated
  Show Answer
  The correct answer is A .