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 1431: On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced? Options:
  A) SO₂ (g) + FeS (s)
  B) SO₃ (g) +FeS(s)
  C) SO₂ (g) + SO₃(g)
  D) SO₂ (g) + H₂S (g)
  E) SO₃(g) + H₂S(g)
  Show Answer
  The correct answer is C .
• Question 1432: A hydrocarbon has an empirical formula CH and a vapour density of 39. Determine its molecular formula.[C = 12, H = 1] Options:
  A) C₂H₆
  B) C₃H₈
  C) C₃H₄
  D) C₆H₆
  Show Answer
  The correct answer is D .
• Question 1433:

  C₃H₅ - COH₃ =CH₂

  The IUPAC nomenclature of the structure above is

  Options:
  A) 3-methybut-3-ene
  B) 2-methylbut-1-ene
  C) 2-ethylprop-1-ene
  D) 2-methylbut-2-ene
  Show Answer
  The correct answer is B .
• Question 1434:

  A metal M displaces zinc from ZnCl, solution, solution

  This shows that

  Options:
  A) electrons flow from zinc to M
  B) M is more electropositive than zinc
  C) M is more electonegative than zinc
  D) zinc is more electropositive than M
  Show Answer
  The correct answer is B .
• Question 1435:

  X is a substance which liberates CO${}_2$ on treatment with concentrated H${}_2$SO${}_4$. A warm solution of X can decolorize acidified KMnO${}_4$. X is

  Options:
  A) HCOOH
  B) NaHCO${}_3$
  C) FeCO${}_3$
  D) H${}_2$C${}_2$O${}_4$
  Show Answer
  The correct answer is D .
• Question 1436:

  

  Choose the correct answer from the options above.

  When Fehling's solution is added to two isomeric carbonyl compounds X and Y with the molecular formula C ₅H ₁₀O, compound X gives a red precipitate while Y does not react. It can be inferred that X is

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is B .
• Question 1437:

  What is the sum of the oxidation numbers in a neutral compound?

  Options:
  A) +2
  B) -1
  C) 0
  D) +1
  Show Answer
  The correct answer is C .
• Question 1438: The bleaching action of chlorine gas is effective due to the presence of Options:
  A) hydrogen chloride
  B) water
  C) air
  D) oxygen
  Show Answer
  The correct answer is B .
• Question 1439: All these are electromagnetic waves except Options:
  A) White light
  B) Photon
  C) X-ray
  D) Infrared
  Show Answer
  The correct answer is B .
• Question 1440:

  2H_2(g) + O_2(g) → 2H₂ O_(g)

  In the reaction above, what volume of hydrogen would be left over when 300 cm³ of oxygen and 1000 cm³ of hydrogen are exploded in a sealed tube?

  Options:
  A) 200 cm³
  B) 400 cm³
  C) 600 cm³
  D) 700 cm³
  Show Answer
  The correct answer is B .