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 1691: 2CL^-_(aq) → CI_2(g) + 2e^-(aq). The above half-cell reaction occuring at the anode during the electrolysis of dilute ZnCI₂ solution is? Options:
  A) ionization
  B) oxidation
  C) reduction
  D) recombination
  Show Answer
  The correct answer is B .
• Question 1692: Phenolphthalein in acidic solution is Options:
  A) red
  B) orange
  C) colourless
  D) yellow
  Show Answer
  The correct answer is C .
• Question 1693: When platinum electrodes are used during the electrolysis of copper (ll) tetraoxosulphate (lV) solution, the solution gets progressively? Options:
  A) acidic
  B) basic
  C) neutral
  D) amphoteric
  Show Answer
  The correct answer is A .
• Question 1694:

  What is the molecular geometry of a molecule with three bonding pairs and no lone pairs around the central atom?

  Options:
  A) Tetrahedral
  B) Trigonal planar
  C) Linear
  D) Octahedral
  Show Answer
  The correct answer is B .
• Question 1695: Which of the following results in the fall of acid rain? Options:
  A) Oxides of lead
  B) Particulate matter
  C) Oxides of sulphur
  D) Gaseous hydrocarbon
  Show Answer
  The correct answer is C .
• Question 1696: The knowledge of half-life can be used to Options:
  A) create an element
  B) detect an element
  C) split an element
  D) irradiate an element
  Show Answer
  The correct answer is A .
• Question 1697: 4.0 g of sodium hydroxide in 250 cm³ of solution contains? Options:
  A) 0.40 moles per dm³
  B) 0.10 moles per dm³
  C) 0.04 moles per dm³
  D) 0.02 moles per dm³
  Show Answer
  The correct answer is A .
• Question 1698:

  At 25^o and zymase as catalyst,

  C₆H₁₂₆ → 2C₂H₅OH + 2CO₂ + energy

  The reaction above represented by the equation above is useful in the production of

  Options:
  A) propanol
  B) butanol
  C) methanol
  D) ethanol
  Show Answer
  The correct answer is D .
• Question 1699:

  An element X has two isotopes, ²⁰₁₀X and ²⁰₁₀X, present in the ratio 1:3. The relative atomic mass of X would be?

  Options:
  A) 20.5
  B) 21.0
  C) 21.5
  D) 22.0
  E) 22.5
  Show Answer
  The correct answer is C .
• Question 1700: Calculate the quantity of electricity in coulombs required to liberate 10g of copper from a copper compound[Cu=64, F = 96500 Cmol^-1] Options:
  A) 32395.5
  B) 30156.3
  C) 60784.5
  D) 15196.5
  Show Answer
  The correct answer is B .