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: Which of the following tests will completely identify anyone of surphur (VI) oxide, hydrogen, carbon (IV) oxide and nitrogen (II) oxide? Options:
  A) Pass each gas into water and test with blue litmus paper
  B) Pass each gas into lime water
  C) Expose each gas to atmospheric air
  D) Pass each gas to concentrated tetraoxosulphate (IV) acid
  Show Answer
  The correct answer is B .
• Question 672:

  Sodium sulphate decahydrate (Na₂SO₄.10 H₂O) on exposure to air loses all its water of crystallization.

  The process of loss is known as

  Options:
  A) efflorescence
  B) hygroscopy
  C) deliquescence
  D) effervescence
  E) dehydration
  Show Answer
  The correct answer is A .
• Question 673: Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen containing compounds because the former contains Options:
  A) water vapour
  B) oxygen
  C) carbon (IV) oxide
  D) rare gases
  Show Answer
  The correct answer is D .
• Question 674:

  In the reaction:

  2Hl_(g) ↔ H_2(g) + l_2(g)' ΔH = 10 kj;

  The concentration of iodine in the equilibrium mixture can be increased by?

  Options:
  A) raising the pressure
  B) raising the temperature
  C) adding a catalyst
  D) lowering the pressure
  Show Answer
  The correct answer is B .
• Question 675: Which of the following is a neutralization reaction? Addition of Options:
  A) nitric acid to hydrochloric acid
  B) nitric acid to sulphuric acid
  C) nitric acid to distilled water
  D) nitric acid to sodium hydroxide
  E) sodium chloride to distilled water
  Show Answer
  The correct answer is D .
• Question 676: Which of the following will shift to the left from dilute tetraoxosulphate (VI) acid? Options:
  A) Lead
  B) Magnesium
  C) Cpper
  D) Gold
  Show Answer
  The correct answer is B .
• Question 677:

  One of the following is not a physical property of monosaccharides?

  Options:
  A) Monosaccharides get charred when heated
  B) Monosaccharides are water-soluble, sweet substances
  C) They are highly vital to the exploration of metals
  D) They can be reduced to sugar alcohols
  Show Answer
  The correct answer is C .
• Question 678:

  Cr₂O₇^2-_(aq) + 14H⁺_(aq) + 6l^-_(aq) → 2Cr³⁺_(aq) + 3l_(g) + 7H₂O_(I).

  The change in the oxidation number of oxygen in the equation above is?

  Options:
  A) 1
  B) 2
  C) 7
  D) 0
  Show Answer
  The correct answer is D .
• Question 679: Ethanoic acid is Options:
  A) tribasic
  B) unionizeable
  C) monobasic
  D) dibasic
  Show Answer
  The correct answer is C .
• Question 680:

  Pure sulphuric acid is a liquid of 1:84 density. What volume of it would be required to prepare 250 cm³ of 2.0 M solution?

  (H = 1, S = 32, O = 16)

  Options:
  A) 2.00
  B) 2.66
  C) 3.00
  D) 3.66
  E) 4.00
  Show Answer
  The correct answer is B .