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 221: The metal whose ore can be concentrated by passing it through a magnetic separator is Options:
  A) Zn
  B) Sn
  C) Cn
  D) Ca
  Show Answer
  The correct answer is B .
• Question 222:

  NH₄Cl_(s) ↔ NH_3(g) + HCL_(g)

  The reaction above can only attain equilibrium if

  Options:
  A) a gaseous reactant is added
  B) one of the products is removed
  C) it is in a closed system
  D) it is an open system
  Show Answer
  The correct answer is C .
• Question 223:

  According to the Kinetic Theory an increase in temperature causes the kinetic energy of particles to

  Options:
  A) decrease
  B) increase
  C) be zero
  D) remain constant
  Show Answer
  The correct answer is B .
• Question 224: In which of the following reactions is sulphur dioxide acting as an oxidizing agent? Options:
  A) SO ₂ + 2HNO₃ →H₂SO₄ + NO₂ + Heat
  B) 2SO₂ + 2H₂O + O₂→ 2H₂SO₄
  C) SO₂ + 2H₂O + CI₂→ H₂SO₄ + 2HCI
  D) SO₂ + 2H₂S → 3S + 2H₂O
  E) SO₂ + H₂O → H₂SO₃
  Show Answer
  The correct answer is D .
• Question 225: Which of the following metals burn with brick red flame? Options:
  A) Pb
  B) Ca
  C) Na
  D) Mg
  Show Answer
  The correct answer is B .
• Question 226:

  2SO_2(g) + O_2(g) $⟺$2SO_3(g)

  $△H=-395.7kJmo{l}^{-1}$

  In the reaction above, the concentration of 2SO_3(g) can be in creased by

  Options:
  A) decreasing the pressure
  B) decreasing the temperature
  C) the addition of catalyst
  D) increasing the temperature
  Show Answer
  The correct answer is B .
• Question 227: Which of the following is NOT an alkali? Options:
  A) NH₃
  B) Mg(OH)₂
  C) Ca(OH)₂
  D) NaOH
  Show Answer
  The correct answer is A .
• Question 228: A good drying agent should be Options:
  A) deliquescent
  B) effervescent
  C) hygroscopic
  D) efflorescent
  Show Answer
  The correct answer is C .
• Question 229: The equilibrium of an endothermic reaction which proceeds with an increase in volume can be shifted in the reverse direction by Options:
  A) increasing the temperature and decreasing the pressure
  B) increasing the pressure and increasing the temperature
  C) decreasing the temperature and increasing the pressure
  D) decreasing the pressure and decreasing the temperature
  Show Answer
  The correct answer is C .
• Question 230: The products of the reaction between dilute sulphuric acid and sodium thiosulphate crystals are? Options:
  A) Na₂SO₄ + SO₂ + O₂ + H₂O
  B) Na₂SO₃ + SO₃ + O₂ + H₂O
  C) Na₂SO₄ + SO₂ + S + H₂O
  D) Na₂SO₄ + SO₃ + S + H₂O
  E) Na₂SO₄ + SO₂ + H₂O only
  Show Answer
  The correct answer is C .