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 1561:

  If the cost of electricity required to discharge 10g of an ion X${}^{3+}$ is N20.00, how much would it cost to discharge 6g of ion Y${}^{2+}$?

  [1 faraday = 96,500C, atomic masses are X = 27, Y = 24]

  Options:
  A) N10.00
  B) N6.00
  C) N20.00
  D) N9.00
  Show Answer
  The correct answer is D .
• Question 1562: Synthetic rubber obtained by the polymerization of chlorobutadiene in the presence of sodium is called? Options:
  A) teflon
  B) isoprene
  C) polythene
  D) neoprene
  Show Answer
  The correct answer is D .
• Question 1563: An element is electronegative if Options:
  A) it has a tendency to exist in the gaseous from
  B) its ions dissolve readily in water
  C) it has a tendency to lose electrons
  D) it has a tendency to gain electrons
  E) it readily froms covalent bonds
  Show Answer
  The correct answer is D .
• Question 1564:

  Al₂O_3(s) + 3H₂SO_4(aq) → Al₂(SO_4(aq)) + 3H_2(I)O

  Al₂O_3(s) + 2NaOH_(aq)) + 3H_2(I)O → 2NaAl(OH)_4(aq)).

  We can conclude from the equations above that Al₂O_3(s) is?

  Options:
  A) an acidic oxide
  B) an amphoteric oxide
  C) a basic oxide
  D) a neutral oxide
  Show Answer
  The correct answer is B .
• Question 1565: Ethene when passed into concentrated H₂SO₄ is rapidly absorbed. The product is diluted with water and then warmed to produce? Options:
  A) ethanol
  B) diethyl ether
  C) ethanal
  D) diethyl sulphate
  Show Answer
  The correct answer is A .
• Question 1566:

  Deliquescent substances are also?

  Options:
  A) efflorescent
  B) anhydrous
  C) hygroscopic
  D) insoluble
  Show Answer
  The correct answer is C .
• Question 1567: A concentrated solution containing H⁺, Cu²⁺,OH^- and CI^- was electrolysed using platiunm electrodes which of the ions will be discharged at the cathods? Options:
  A) H⁺
  B) Cu²⁺
  C) OH^-
  D) CI^-
  Show Answer
  The correct answer is B .
• Question 1568:

  When 10g of sodium hydroxide is dissolved in 1000cm³ of water, the sodium formed is approximately

  [Na = 23, H = 1, O = 16]

  Options:
  A) 0.01 mol dm^-3
  B) 0.10 mol dm^-3
  C) 0.25 mol dm^-3
  D) 0.50 mol dm^-3
  Show Answer
  The correct answer is C .
• Question 1569: Which of the following compounds gives a yellow residue when heated and also reacts with aqueous sodium hydroxide to give a white gelatinous precipitate soluble in excess sodium hydroxide solution? Options:
  A) (NH₄)CO₃
  B) ZnCO₃
  C) Al₂(SO₄)₃
  D) PbCO3
  Show Answer
  The correct answer is B .
• Question 1570: In the industrial production of H₂ from natural gas the CO₂ produced along with the H₂ is removed by Options:
  A) washing under pressure
  B) drying over phosphorus (V) oxide
  C) passing the mixture into lime water
  D) using ammonical copper (I) chloride
  Show Answer
  The correct answer is A .