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 21: A characteristic reaction of the compounds with the general formula C_nH_2n is Options:
  A) Esterification
  B) Polymerization
  C) Decarboxylation
  D) Substitution
  Show Answer
  The correct answer is B .
• Question 22: The idea of planetary electron was that of Options:
  A) Rutherford
  B) Thompson
  C) Bohr
  D) Dalton
  Show Answer
  The correct answer is A .
• Question 23: Fluorine does not occur in the free state in nature because Options:
  A) it is a poisonous gas
  B) it belongs to the halogen family
  C) it is inert
  D) of its high reactivity
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  The correct answer is D .
• Question 24:

  Which of the following describes the chemical property of acids?

  Options:
  A) None of the above
  B) Acid + XCO${}_3$ $\to$ Salt + H${}_2$O + NH${}_3$
  C) Acid + NaOH $\to$ Normal salt + CO${}_2$
  D) Acid + X${}_n$CO${}_3$ $\to$ Salt + H${}_2$O + CO${}_2$
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  The correct answer is D .
• Question 25: The electronic configuration of an elements is 1s²2s²2p⁶3s²3p³. How many unpaired electrons are there in the element? Options:
  A) 5
  B) 4
  C) 3
  D) 2
  Show Answer
  The correct answer is C .
• Question 26:

  

  Use the figure above to answer this question. Which of the following is NOT a monomer?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is A .
• Question 27: The chemical used for coagulation in water purification is Options:
  A) Aluminium tetraoxosulphate (VI)
  B) Copper tetraoxosulphate (VI)
  C) Sodium tetraoxosulphate (VI)
  D) Calcium tetraoxosulphate (VI)
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  The correct answer is A .
• Question 28:

  

  At what temperature is the solubility of potassium trioxonitrate(V ) equal to that of sodium trioxonitrate (V)?

  Options:
  A) 0${}^o$c
  B) 30${}^o$c
  C) 40${}^o$c
  D) 45${}^o$c
  Show Answer
  The correct answer is D .
• Question 29: Which of the following statements is NOT correct? Options:
  A) The average kinetic energy of a gas is directly proportional to its temperature
  B) At constant tempearture, the volume of a gas increases as the pressure increases
  C) The pressure of a gas is inversely proportional to its volume
  D) The temperature of a gas is directly proportional to its volume
  E) The collisions of molecules with each other are inelastic
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  The correct answer is B .
• Question 30: Phosphorus burns in oxygen according to the equation P₄ + 50₂ → P₄O₁₀. How many litres of oxygen will be required at S.T.P for complete oxidation of 12.4g of phosphorus? [P = 31,O = 16 and molar volume of a gas at S.T.P = 22.4 litres] Options:
  A) 5. 20
  B) 11. 20
  C) 2. 24
  D) 20. 20
  E) 6. 20
  Show Answer
  The correct answer is B .