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 1061: The pollutants that are likely to be present in an industrial environment are? Options:
  A) H₂S,SO₂ and oxides of nitrogen
  B) NH₃, HCI and CO
  C) CO₂, NH₃ and H₂S
  D) dust, NO and CI₂
  Show Answer
  The correct answer is A .
• Question 1062: 2H₂S_(g) + SO_2(g) → 3S_(s) + 2H₂O_(I). The above reaction is? Options:
  A) a redox reaction H₂S is the oxidant and SO₂ is the reductant
  B) a redox reaction in which SO₂ is the oxidant and H₂S is the reductant
  C) not a redox reaction because there is no oxidant in reaction equation
  D) not a redox because there is no reductant in the reaction equation
  Show Answer
  The correct answer is B .
• Question 1063: When a crystal was added to the clear solution of its salt, the crystal did not dissolve and the solution remained unchange. This showed that the solution was Options:
  A) supersaturated
  B) concentrated
  C) unsaturated
  D) saturated
  Show Answer
  The correct answer is D .
• Question 1064: A solid begins to melt when? Options:
  A) constituent particles acquires a greater kinetic energy
  B) energy of vibration of particles of the solid is less than the intermolecular forces
  C) constituent particles acquires energy above the average kinetic energy
  D) energy of vibration of particles of the solid equals the intermolecular forces
  Show Answer
  The correct answer is A .
• Question 1065:

  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 1066:

  Aluminium does not react with either dilute or concentrated trioxonitrate (V) acid because

  Options:
  A) it is insoluble in either dilute or concentrated trioxonitrate (V) acid
  B) it is lower than hydrogen in the electrochemical series
  C) the reaction with trioxonitrate (V) acid has a light activation energy
  D) an insoluble oxide is formed on its surface which renders it passive
  Show Answer
  The correct answer is D .
• Question 1067:

  

  In the diagram, the function of the concentrated H₂SO₄ is to

  Options:
  A) purify the gas
  B) dry the gas
  C) liquefty the gas
  D) remove odour
  Show Answer
  The correct answer is B .
• Question 1068:

  The two ions responsible for hardness in water are

  Options:
  A) Ca${}^{2+}$ and / or Mg${}^{2+}$
  B) K${}^{+}$ and / or Mg${}^{2+}$
  C) Ca${}^{2+}$ and / or Li${}^{+}$
  D) Ca${}^{2+}$ and / or Na${}^{+}$
  Show Answer
  The correct answer is A .
• Question 1069:

  Which of the following alkaline metals react more quickly spontaneously with water?

  Options:
  A) Calcium
  B) Beryllium
  C) Magnesium
  D) Strontium
  Show Answer
  The correct answer is A .
• Question 1070:

  2Na ₂ O _2(s) + 2H ₂ O ₂₍₁₎ → 4 NaOH_(s) +O_2(s)

  The substance that is oxidized in the reaction above is

  Options:
  A) 2NaO_2(s)
  B) NaOH(aq)
  C) H₂O₍₁₎
  D) O_2(g)
  Show Answer
  The correct answer is A .