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 341: Which of the following are isomers? Options:
  A) Ethanol and dimethyl ether
  B) Benzene and methybenzene
  C) Ethanol and propanone
  D) Trichloromethane and tetrachloromethane
  Show Answer
  The correct answer is A .
• Question 342: What is the correct IUPAC name for NO₂^-? Options:
  A) Dioxonitrate (IV) ion
  B) Trioxonitrate (III) ion
  C) Trioxonitrate (IV) ion
  D) Dioxonitrate (II) ion
  Show Answer
  The correct answer is D .
• Question 343:

  During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment

  Options:
  A) the litmus turns blue but no gas is evolved
  B) the litmus turns blue and oxygen is evolved
  C) the litmus turns blue and hydrogen is evolved
  D) the litmus turns red and oxygen is evolved
  Show Answer
  The correct answer is D .
• Question 344: Arrange HCI, CH₃COOH, C₆H₅CH₃ in order of increasing conductivity. Options:
  A) HCI, CH₃COOH, C₆H₅CH₃
  B) C₆H₅CH₃, HCI, CH₃COOH
  C) C₆H₅CH₃, CH₃COOH, HCI
  D) CH₃COOH, C₆H₅CH₃, HCI
  Show Answer
  The correct answer is C .
• Question 345: Ethanoic acid is Options:
  A) tribasic
  B) unionizeable
  C) monobasic
  D) dibasic
  Show Answer
  The correct answer is C .
• Question 346: The electron configuration of ₂₂X ²⁺ ion is Options:
  A) 1s² 2s²2p⁶ 3s² 3p⁶ 4s² 3d²
  B) 1s² 2s²2p⁶ 3s² 3p⁶ 4s² 3d¹
  C) 1s² 2s²2p⁶ 3s² 3p⁶
  D) 1s² 2s²2p⁶ 3s² 3p⁶ 4s²
  Show Answer
  The correct answer is D .
• Question 347: A reaction takes places spontaneously if?
  Options:
  A) ∆G = O
  B) ∆S < O and ∆H > O
  C) ∆H < T ∆S
  D) ∆G > O
  Show Answer
  The correct answer is C .
• Question 348: Which of the following can be obtained by fractional distillation? Options:
  A) Nitrogen from liquid air
  B) Sodium chloride from sea water
  C) Iodine from a solution of Iondine in carbon tetrachloride
  D) Sulphur from a solution of sulphur incarbon disulphide
  Show Answer
  The correct answer is A .
• Question 349:

  H${}^{+}$ + OH${}^{-}$ H${}_2$O

  The equation above illustrates

  Options:
  A) precipitation
  B) hydration
  C) hydrolysis
  D) neutralization
  Show Answer
  The correct answer is D .
• Question 350: What are the possible oxidation numbers of an element if its atomic number is 17? Options:
  A) -1 and 7
  B) -1 and 6
  C) -3 and 5
  D) -2 and 6
  Show Answer
  The correct answer is A .