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 91:

  Diamond is a bad conductor of electricity because its bonding electrons are used in

  Options:
  A) crystal lattice formation
  B) covalent bond formation
  C) metallic bond formation
  D) coordinate bond formation
  Show Answer
  The correct answer is B .
• Question 92:

  Sodium sulphate decahydrate (Na₂SO₄.10 H₂O) on exposure to air loses all its water of crystallization.

  The process of loss is known as

  Options:
  A) efflorescence
  B) hygroscopy
  C) deliquescence
  D) effervescence
  E) dehydration
  Show Answer
  The correct answer is A .
• Question 93:

  Helium is used in observation of ballons because it is?

  Options:
  A) Light and combustible
  B) light and non-combustible
  C) heavy and combustible
  D) heavy and non-combustible
  Show Answer
  The correct answer is B .
• Question 94: Which of the following is NOT used as a raw material in the Solvay process? Options:
  A) Ammonia
  B) Sodium chloride
  C) Calcium trioxocarbonate (IV)
  D) Sodium trioxocarbonate (IV)
  Show Answer
  The correct answer is D .
• Question 95:

  The reaction $2H_{2}S+S{O}_2\to 3S+2H_{2}O$ is

  Options:
  A) not a redox reaction because there is no oxidant in the reaction
  B) not a redox reaction because there is no reductant in the reaction
  C) a redox reaction in which H${}_2$S is the oxidant and SO${}_2$ is the reductant
  D) a redox reaction in which SO${}_2$ is the oxidant and H${}_2$S is the reductant
  Show Answer
  The correct answer is D .
• Question 96:

  C_(s) + H₂O_(g) → H_2(g) + CO_2(g)

  ΔG for the reaction above at 1300k is -43KJ. At this temperature, the reaction is

  Options:
  A) not feasible
  B) at equilibrium
  C) feasible
  D) exothermic
  Show Answer
  The correct answer is C .
• Question 97: Neutral atoms of neon with atomic number 10 have the same number of electron as Options:
  A) O²⁺
  B) Ca²⁺
  C) K⁺
  D) Mg²⁺
  Show Answer
  The correct answer is D .
• Question 98: An amphoteric oxide is an? Options:
  A) amorphous oxide of a metal
  B) amorphous oxide of a non-mental
  C) oxide that is insoluble in water
  D) oxide that behaves both as a base as well as an acid
  E) oxide that loses its oxygen on sublimation
  Show Answer
  The correct answer is D .
• Question 99:

  The size (diameter) of five elements are in the order R < T < W < X < Y, Y being the largest. If each atom has an electron situated on its circumference, and neglecting other factors, which of the atoms will lose its electron most reluctantly?

  Options:
  A) R
  B) T
  C) W
  D) X
  E) Y
  Show Answer
  The correct answer is A .
• Question 100: Which of the following statements applies during the electroysis of sodium hydroxide sodium hydroxide solution using platinum electrodes? Options:
  A) Na⁺ ions are discharged at the cathode
  B) Hydrogen ions are discharged at the anode
  C) the concentration of sodium hydroxide decrease at both electrode compartments
  D) the concentration of sodium hydroxide increases at the cathode only
  E) the concentration of sodium hydroxide increases at the anode only
  Show Answer
  The correct answer is D .