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 1081: Which of the following classes of organic compounds undergoes rapid oxidation with bromine water? Options:
  A) alcohols
  B) alkenes
  C) carboxylic acids
  D) esters
  E) alkanes
  Show Answer
  The correct answer is B .
• Question 1082:

  When anhydrous cobalt chloride paper is exposed to water, what color change is observed?

  Options:
  A) From pink to blue
  B) From white to blue
  C) From blue to white
  D) From blue to pink
  Show Answer
  The correct answer is D .
• Question 1083:

  The reactions involving simultaneous oxidation and reduction?

  Options:
  A) Automatic reactions
  B) Alternate reactions
  C) Reduction agency
  D) Redox reactions
  Show Answer
  The correct answer is D .
• Question 1084: How many lone pairs of electron are there on the central atom of the H₂O molecules? Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is B .
• Question 1085: Geometric isomerism can exist in Options:
  A) hex-3-ene
  B) hexane
  C) prop-l-ene
  D) 3-methyl but -l-ene
  Show Answer
  The correct answer is A .
• Question 1086:

  The heat of formation of ethene, C${}_2$H${}_4$ is 50 kJmol${}^{-1}$, and that of ethane, C${}_2$H${}_6$ is -82kJmol${}^{-1}$. Calculate the heat evolved in the process:

  C${}_2$H${}_4$ + H${}_2$ $\to$ C${}_2$H${}_6$

  Options:
  A) -122kJ
  B) -132kJ
  C) -88kJ
  D) -60kJ
  Show Answer
  The correct answer is B .
• Question 1087:

  Which transition metal is known for its multiple colorful oxidation states and compounds used in pigments and paints?

  Options:
  A) Silver (Ag)
  B) Copper (Cu)
  C) Gold (Au)
  D) Zinc (Zn)
  Show Answer
  The correct answer is B .
• Question 1088: In the extraction of iron, which of the following reactions does NOT take place in the blast furnace? Options:
  A) CO₂ + C → 2CO
  B) 2Fe₂O₃ + 3C → 4Fe + 3CO₂
  C) Fe₂O₃ + 3C → 2Fe + 3CO₂
  D) CaCO₃ → CaO + CO₂
  E) CaO + SiO₂ → CaSiO₃
  Show Answer
  The correct answer is B .
• Question 1089:

  What is the empirical formula of a compound containing 40.00% carbon, 6.67% hydrogen, and 53.33% oxygen by mass?

  Options:
  A) C${}_4$H${}_8$O${}_4$
  B) CH${}_2$O
  C) C${}_2$H${}_4$O${}_2$
  D) C${}_3$H${}_6$O${}_3$
  Show Answer
  The correct answer is B .
• Question 1090:

  C₂H₅ - C = CH₂

  CH₃The correct name of the compound with the above structural formula is

  Options:
  A) 2-methylbut -1-ene
  B) 2-methylbut -2-ene
  C) 2-methylbutane
  D) 2-ethylprop-1 -ene
  E) 2-ethylprop-2-ene
  Show Answer
  The correct answer is A .