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 851: What is discharged at the cathode during the electrolysis of copper (ll) tetraoxosulphate (VI) solution? Options:
  A) Cu ²⁺ only
  B) H + only
  C) Cu ²⁺ and H
  D) Cu ²⁺ and SO ^2-
  Show Answer
  The correct answer is A .
• Question 852:

  Elements X and Y have electronic configurations 1s${}^2$2s${}^2$2p${}^4$ and 1s${}^2$2s${}^2$2p${}^6$3s${}^2$3p${}^1$ respectively. When they combine, the formula of the compound formed is

  Options:
  A) XY
  B) X${}_2$Y
  C) Y${}_2$X${}_3$
  D) X${}_2$Y${}_3$
  Show Answer
  The correct answer is C .
• Question 853: In the electrolysis of a concentrated solution of sodium chloride using electrodes, which of the following ions are discharged at the cathode and anode respectively? Options:
  A) Na⁺ and Cl^-
  B) Na⁺ and OH^-
  C) H⁺ and OH^-
  D) H⁺ and Cl^-
  Show Answer
  The correct answer is D .
• Question 854: Which of the following substances are all made by the process of polymerization? Options:
  A) Nylon and soap
  B) Ethanoic acid margarine and ethanol
  C) Nylon and artificial rubber
  D) Soap and butane
  E) Margarine and nylon
  Show Answer
  The correct answer is C .
• Question 855: The reaction of zinc with copper (ll) ions in aqueous solution can be represented as follows: Cu ²⁺(aq) +Zn (s) → Cu(s) + Zn ²⁺(aq).Which of the following is the most complete description of this reaction? Options:
  A) Cpper (ll) ions are being reduced
  B) Zinc is being oxidized.
  C) Copper (ll) ions and zinc are being reduced
  D) copper (ll) ions and zinc are being oxidized
  E) copper(ll) ions are being reduced and zinc oxidized
  Show Answer
  The correct answer is E .
• Question 856: Which of the following derivatives of nitrogen affords an aqueous solution having a pH of less that 7? Options:
  A) N₂O
  B) NO
  C) NO₂
  D) NaNO₃
  E) NH₃
  Show Answer
  The correct answer is C .
• Question 857: The gas that is the most dangerous pollutant to human is Options:
  A) sulphur (IV) oxide
  B) carbon (IV) oxide
  C) nitrogen (II) oxide
  D) hydrogen sulphide
  Show Answer
  The correct answer is D .
• Question 858:

  What is the IUPAC name for the compound CCl${}_4$?

  Options:
  A) Tetrahydrochloride
  B) Tetrachloromethane
  C) Carbon tetrachloride
  D) Chloroform
  Show Answer
  The correct answer is B .
• Question 859: Which of the activities is commonly used as a nuclear fuel Options:
  A) uranium
  B) palladium
  C) actium
  D) thorium
  Show Answer
  The correct answer is A .
• Question 860: Which of the following molecules has two other positional isomers? Options:
  A) CH₃CH₂Br
  B) CH₃CHBrCH₃
  C) CBr₂F₂
  D) CH₂CHBrCH₂Br
  Show Answer
  The correct answer is D .