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 11: A compound gives an orange-red colour to non-luminous flame. This compound is likely to contain Options:
  A) Na⁺
  B) Ca²⁺
  C) Fe³⁺
  D) Fe²⁺
  Show Answer
  The correct answer is B .
• Question 12: The substance ZnO dissolves in sodium hydroxide solution and mineral acid solution to give soluble products in each case. ZnO is therefore referred to as Options:
  A) an allotropic oxide
  B) an amphoteric oxide
  C) a peroxide
  D) a dioxide
  Show Answer
  The correct answer is B .
• Question 13: Which of the following is found in cotton Options:
  A) Starch
  B) Cellulose
  C) Fat
  D) Oil
  Show Answer
  The correct answer is B .
• Question 14: The stability of the noble gases is due to the fact that they Options:
  A) have no electron in their outermost shells
  B) have duplet or octet electron configurations
  C) belong to group zero of the periodic table
  D) are volatile in nature
  Show Answer
  The correct answer is B .
• Question 15: In recharging a lead-acid accumulator, the reaction at the cathode can be represented as Options:
  A) Pb²⁺_(aq) + SO^2-_4(aq) →PbSO_4(s)
  B) Pb²⁺_(aq) + 2e^- →Pb_(s)
  C) Pb²⁺_(aq) + 2H₂O_(l) → PbO_2(s) + 4H⁺_(aq) + 4e^-
  D) Pb_(s) → Pb²⁺_(aq) + 2e^-
  Show Answer
  The correct answer is D .
• Question 16: Which of the following substances is the most abundant in the universe? Options:
  A) Carbon
  B) Air
  C) Water
  D) Oxygen
  E) Hydrogen
  Show Answer
  The correct answer is E .
• Question 17: One of the following techniques can be used to show that chlorophyll pigment is a mixture of chemical compounds and not a single coloured compound Options:
  A) cystallization
  B) hydrolysis
  C) sublimation
  D) filtration
  E) chromatography
  Show Answer
  The correct answer is E .
• Question 18: Which among the elements 1. Carbon 2. Oxygen 3. Copper 4. Bromine 5. Zinc, will NOT react with either water or steam? Options:
  A) 1 and 2
  B) 2 and 3
  C) 3 and 4
  D) 1, 2, and 3
  E) 2, 3, and 5
  Show Answer
  The correct answer is B .
• Question 19: Which of the following represents saponification? Options:
  A) Reaction of carboxylic acids with sodium hydroxide
  B) Reaction of alkanoates with acid
  C) Reaction of alkanoates with alcohols
  D) Reaction of alkanoates with sodium hydroxide
  Show Answer
  The correct answer is D .
• Question 20: Which of the following substances is a mixture? Options:
  A) Sulphur powder
  B) Bronze
  C) Distilled water
  D) Ethanol
  Show Answer
  The correct answer is B .