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 1001: 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 1002:

  2Cl_2(g) + 2H₂O_(g) 4HCl_(g) + O_2(g)

  ∆H° = +115KJ mol^-1. In the above equilibrium reaction, a decrease in temperature will?

  Options:
  A) favour the reverse reaction
  B) favour the forward reaction
  C) have no effect on the equilibrium state
  D) double the rate of the reverse raection
  Show Answer
  The correct answer is A .
• Question 1003: The type of iron that is best suited for welding, making nails, chains and iron rods is Options:
  A) pig iron
  B) wrought iron
  C) cast iron
  D) iron pyrites
  Show Answer
  The correct answer is B .
• Question 1004: The octane number of a fuel whose performance is the same as that of a mixture of 55 g of 2,2,4- trimethly pentane and 45 g of n-heptane is ? Options:
  A) 45
  B) 55
  C) 80
  D) 100
  Show Answer
  The correct answer is B .
• Question 1005:

  What is the trend for ionization energy across a period in the periodic table?

  Options:
  A) Increases from left to right.
  B) Remains constant
  C) Varies randomly
  D) Decreases from left to right
  Show Answer
  The correct answer is A .
• Question 1006: The correct order of increasing boiling points of the following compounds C₃H₇OH, C₇H₁₆ and C₄H₁₀ is Options:
  A) C₃H₇OH → C₄H₁₀ → C₇H₁₀
  B) C₄H₁₀ → C₇H₁₆ → C₃H₇OH
  C) C₇H₁₆ → C₃H₇OH → C₄H₁₀
  D) C₄H₁₀ → C₃H₇OH → C₇H₁₆
  Show Answer
  The correct answer is D .
• Question 1007: Copper is displaced from the solution of its salts by most metals because it Options:
  A) is a transition element
  B) is at the bottom of the activity series
  C) is very reactive
  D) has completely filled 3d-orbitals
  Show Answer
  The correct answer is B .
• Question 1008: The salt formed from a reaction between citric acid and sodium hydroxide in solution will be Options:
  A) acidic
  B) basic
  C) complex
  D) neutral
  Show Answer
  The correct answer is B .
• Question 1009:

  The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is

  Options:
  A) Na${}_2$SO${}_4$
  B) Na${}_2$SO${}_3$
  C) Na${}_2$S
  D) Na${}_2$CO${}_3$
  Show Answer
  The correct answer is B .
• Question 1010: The Avogadro number of 24g of magnesium is the same as that of Options:
  A) 1g of hydrogen molecules
  B) 16g of oxygen molecules
  C) 32g of oxygen molecules
  D) 35.5g of chlorine molecules
  Show Answer
  The correct answer is C .