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 1921: Consider the following equation H₂O + 2Fe²⁺ + Cl₂ ↔ 2Fe³⁺ + 2Cl^- + H₂O. The only ion which behaves as an oxidising agent is Options:
  A) Fe²⁺
  B) Cl₂
  C) Fe³⁺
  D) Cl^-
  E) H₂O
  Show Answer
  The correct answer is B .
• Question 1922:

  What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?

  Options:
  A) Fractional crystallization
  B) Fractional distillation
  C) Filtration
  D) Evaporation
  Show Answer
  The correct answer is A .
• Question 1923: An electron can be added to a halogen atom to form a halide ion with Options:
  A) 2 valence electrons
  B) 3 valence electrons
  C) 7 valence electrons
  D) 8 valence electrons
  Show Answer
  The correct answer is D .
• Question 1924: One note of a hydrocarbon 36g of carbon and its density is 20. The structure of hydrocarbon is (organic chemical) Options:
  A) CH3C = CH
  B) CH3CH = CH2
  C) CH3CH2C = CH
  D) CH33CH2CH3
  Show Answer
  The correct answer is A .
• Question 1925:

  The compounds made up of only carbon and hydrogen are called?

  Options:
  A) Carbon compounds
  B) Hydrocarbons
  C) Atoms
  D) Carbon hydrolysis
  Show Answer
  The correct answer is B .
• Question 1926: Which of the following metals burns with brick red Options:
  A) Pb
  B) Ca
  C) Na
  D) Mg
  Show Answer
  The correct answer is B .
• Question 1927: In the electrolytic extraction of cacium from calcium chloride, the cathode is Options:
  A) zinc
  B) graphite
  C) platinum
  D) iron
  Show Answer
  The correct answer is D .
• Question 1928: Two equal bulbs, one containing ammonia and the other one opened mouth-to mouth to each other at temperature the entropy in the mixture of gases is likely to Options:
  A) remain unchanged
  B) increase
  C) decrease
  D) charge
  Show Answer
  The correct answer is A .
• Question 1929: Which of the following combination of gases is used for metal welding? i. Oxygen and ethyne, ii. Hydrogen and ethyne, iii. Hydrogen and oxygen, iv. Ethyne, hydrogen and oxygen. Options:
  A) i and ii
  B) ii and iv
  C) i and iii
  D) ii and iv
  Show Answer
  The correct answer is A .
• Question 1930: Which of the following best explains the increase in the rate of a chemical reaction as the temperature rises? Options:
  A) The bonds in the reacting molecules are more readily broken
  B) The molecular collisions become more violent
  C) A lower proportion of the molecules has the necessary minimum energy to react
  D) The collision frequency of the molecules increase
  Show Answer
  The correct answer is D .