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 401: Which of the following ions require the largest quantity of electricity for discharge at an electrode? Options:
  A) 4.0 moles of Cl^-
  B) 3.0 moles of Na⁺
  C) 2.5 moles of Cu²⁺
  D) 2.0 moles of Al³⁺
  Show Answer
  The correct answer is C .
• Question 402: Which of the following is not an alkali? Options:
  A) Ca(OH)₂
  B) NH₃
  C) NaOH
  D) Al(OH)₃
  Show Answer
  The correct answer is B .
• Question 403:

  CuO_(s) + H_2(g) ↔ Cu_(s) + H₂O_(l)

  What is the effect of increasing the pressure on the equilibrium reaction above?

  Options:
  A) The equilibrium is shifted to the left
  B) The equilibrium is shifted to the right
  C) There is no effect
  D) More H_2(g) is produced
  Show Answer
  The correct answer is C .
• Question 404:

  Which of the following reactions is an oxidation process?

  Options:
  A) 2H${}^{+}$ + 2e${}^{-}$ $\to$ H${}_2$
  B) 2O${}^{2-}$ + 4e${}^{-}$ $\to$ O${}_2$
  C) OCl${}^{-}$ + H${}_2$O + 2e${}^{-}$ $\to$ 2OH${}^{-}$ + Cl${}^{-}$
  D) Cl + e${}^{-}$ $\to$ Cl${}^{-}$
  Show Answer
  The correct answer is B .
• Question 405: An example of a hygroscopic substance is Options:
  A) CuO _(S).
  B) MgCL_2(S).
  C) CaCL_2(S).
  D) NaOH_(S).
  Show Answer
  The correct answer is A .
• Question 406: Sodium hydroxide is prepared commercially from sodium chloride solution by? Options:
  A) electrolysis using mercury as cathode
  B) hydrolysis in steam using a catalyst
  C) electrolysis using iron as anode
  D) treating sodium chloride with ammonia and carbon (IV) oxide
  Show Answer
  The correct answer is A .
• Question 407:

  Which of the following is a characteristic property of acids?

  Options:
  A) Turn litmus paper blue
  B) Bitter taste
  C) pH value above 7
  D) React with metals to produce hydrogen gas
  Show Answer
  The correct answer is D .
• Question 408:

  What is the chemical name for the compound CuCO${}_3$?

  Options:
  A) Copper (iii) carbonate
  B) Copper (ii) carbonate
  C) Copper (i) carbonate
  D) Copper
  Show Answer
  The correct answer is B .
• Question 409: The compound produced when sodium peroxide is heated with excess sodium is Options:
  A) Na₂CO₃
  B) Na₂O
  C) NaNO₂
  D) NaOH
  Show Answer
  The correct answer is B .
• Question 410:

  Na₂S₂O_3(aq) + 2HCl_(aq) → 2NaCl_(aq) + H₂O_(l)

  Which of the following would introduce the greatest increase in the rate of the chemical reaction above?

  Options:
  A) An increase in temperature and decrease in the concentration of the reactant
  B) A decrease in the volume and increase in the pressure of the reactant
  C) A decrease in the temperature and an incease in the concentration of the reactant
  D) An increase in temperature and an increase in the concentration of the reactant
  Show Answer
  The correct answer is D .