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 61: Aluminium hydroxide is used in the dyeing industry as a Options:
  A) dye
  B) dispersant
  C) salt
  D) mordant
  Show Answer
  The correct answer is D .
• Question 62: Calcium hydroxide and ammonium chloride when heated together will give an important product. This compound may be obtained dry by Options:
  A) dissolving it in water, recrystallizing it and then drying in the oven
  B) passing it through a concentrated aqueous solution of sodium hydroxide
  C) passing it through calcium oxide
  D) passing it through concentrated sulphuric acid
  E) passing it through anhydrous calcium choride
  Show Answer
  The correct answer is C .
• Question 63: In the purification of impure samples of ethyl ethanoate synthesized by esterification, concentrated sodium trioxocarbonate (IV) solution is used to remove Options:
  A) water
  B) basic impurities
  C) acidic impurities
  D) ethoxyethane
  Show Answer
  The correct answer is C .
• Question 64:

  Which of these alloys contains copper?

  Options:
  A) solder
  B) steel
  C) permallory
  D) bronze
  Show Answer
  The correct answer is D .
• Question 65:

  

  The compound above is an

  Options:
  A) ether
  B) ester
  C) alkanal
  D) alkanol
  Show Answer
  The correct answer is B .
• Question 66: The number of hydrogen ions in 4.9 g of tetraoxosulphate (IV) acid is?(S = 32, O =16, H = 1, Na = 6.02 x 10₂₃ Options:
  A) 3.01 x 10₂₂
  B) 6.02 x 10₂₂
  C) 3.01 x 10₂₃
  D) 6.01 x 10₂₃
  Show Answer
  The correct answer is B .
• Question 67: Under high pressure, real gases do not obey gas laws because their molecules? Options:
  A) have become more energetic
  B) have become less energetic
  C) have become smaller in size
  D) decompose into atoms
  E) start repelling each other
  Show Answer
  The correct answer is B .
• Question 68: An effect of thermal pollution on water bodies is that the Options:
  A) volume of water reduces
  B) volume of chemical waste increase
  C) level of oxides of nitrogen increase
  D) level of oxygen reduces
  Show Answer
  The correct answer is D .
• Question 69: In the electrolysis of brine, the anode is Options:
  A) platinum
  B) copper
  C) zinc
  D) carbon
  Show Answer
  The correct answer is D .
• Question 70:

  Given that 15.00 cm³ of H₂

  SO₄ was required to completely neutralize 25.00 cm³ of 0.125 mol dm^-3 NaOH, calculate the molar concentration of the acid solution:

  Options:
  A) 0.925 mol dm^-3
  B) 0.156mol dm^-3
  C) 0.104 mol dm^-3
  D) 0.023 mol dm^-3
  Show Answer
  The correct answer is C .