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 671: Complete oxidation of propan -1- ol gives? Options:
  A) propanal
  B) propan-2-al
  C) propan-1-one
  D) propanoic acid
  Show Answer
  The correct answer is D .
• Question 672:

  What is the sum of the oxidation numbers in a neutral compound?

  Options:
  A) +2
  B) -1
  C) 0
  D) +1
  Show Answer
  The correct answer is C .
• Question 673:

  If a given quantity of electricity liberates 0.65g of Zn²⁺, what amount of Hg²⁺ would be liberated by the same quantity of current?

  [Zn = 65, Hg = 201]

  Options:
  A) 1.00g
  B) 2.10g
  C) 4.02g
  D) 8.04g
  Show Answer
  The correct answer is B .
• Question 674: In an attempt to remove sugar from a breaker containing a quantity of sand and sugar, 2 M ammonium chloride solution was accidentally added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture? Options:
  A) Fractional distillation
  B) crystallization
  C) Filtration followed by evaporation
  D) Evaporation followed by sublimation
  E) Filtration followed by sublimation
  Show Answer
  The correct answer is D .
• Question 675: The brown fumes given off when trioxonitrate (V) acid is heated consist of ? Options:
  A) NO₂ and O₂
  B) H₂O and NO₂
  C) NO_2' O₂ and H₂O
  D) NO, NO₂ and H₂O
  Show Answer
  The correct answer is C .
• Question 676:

  H_2(g) + Br_2(g) → 2HBr_(g)

  The above reaction is carried out at 25^oC. ΔH is -72 kJ mol^-1 and ΔS is - 106 J mol^-1K^-1, the reaction will

  Options:
  A) not proceed spontaneously at the given
  B) proceed spontaneously at the given temperature
  C) proceed in the reverse direction at the given temperature
  D) proceed spontenously at lower temperature
  Show Answer
  The correct answer is A .
• Question 677:

  To what volume must 300cm${}^3$ of 0.60M sodium hydroxide solution be diluted to give a 0.40M solution?

  Options:
  A) 450cm${}^3$
  B) 300cm${}^3$
  C) 200cm${}^3$
  D) 150cm${}^3$
  Show Answer
  The correct answer is A .
• Question 678:

  The shape of ammonia molecule is?

  Options:
  A) Trigonal planar
  B) Octahedral
  C) Square planar
  D) Tetrahedral
  Show Answer
  The correct answer is A .
• Question 679: The gaseous pollutant sulphur (IV)oxide is most likely to be detected in fairly reasonable quantities in the area around a plant for the Options:
  A) extraction of aluminium from bauxite
  B) production of margarine
  C) smelting of copper
  D) production of chlorine from brine
  Show Answer
  The correct answer is C .
• Question 680: What volume of 0.5 MH₂SO₄ will exactly neutralize 20cm³ of 0.1 MNaOH Solution? Options:
  A) 2.0cm³
  B) 5.0cm³
  C) 6.8cm³
  D) 8.3cm³
  Show Answer
  The correct answer is A .