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 31: Which of the following in aqueous solution is neutral to litmus? Options:
  A) NH₄CI
  B) NaCO₃
  C) FeCl₃
  D) NaCl
  Show Answer
  The correct answer is D .
• Question 32: The postulate of Dalton's atomic theory which still holds is that Options:
  A) atoms can neither be created nor destroyed
  B) the particles of the same element are exactly alike
  C) particles of different elements combine in simple whole number ratio
  D) all elemets are made of small indivisible particles
  Show Answer
  The correct answer is A .
• Question 33: A liquid that will dissolve fat is Options:
  A) Hydrochloric acid
  B) Calcium hydroxide
  C) Kerosene
  D) Water
  Show Answer
  The correct answer is B .
• Question 34:

  Equal volumes of CO,SO₂, and H₂S were released into a room at the same point and time. Which of the following gives the order of diffusion of the gases to the opposite corner of the room?

  (S = 32, C = 12, O = 16, N = 14, H = 1)

  Options:
  A) CO, SO₂,NO₂,H₂S
  B) SO₂,NO₂,H₂S,CO
  C) CO,H₂S,SO₂,NO₂
  D) CO,H₂S,NO₂,SO₂
  Show Answer
  The correct answer is D .
• Question 35: The solution of a sample in a tube will be identified as a chloride if it gives Options:
  A) a white precipitate on addition of AgNO₃ and barium chloride solutions
  B) a white precipiate when acidified with HCI, and then AgNO₃ solution added
  C) a white precipitate when acidified with dilute HNO₃ and then AgNO₃ solution added
  D) a white precipitate when acidified with dilute H₂SO₄ and then barium nitrate solution added
  E) a pungent smell of chlorine gas when dilute HCI and MnO₂ are added
  Show Answer
  The correct answer is C .
• Question 36:

  A solution X, on mixing with AgNO${}_3$ solution gives a white precipitate soluble in aqueous NH${}_3$, a solution Y, when also added to X, also gives a white precipitate which is soluble when heated solutions X and Y respectively contain

  Options:
  A) Al${}^{3+}$, Cl${}^{-}$
  B) Hg${}^{+}$, SO${}_4^{2-}$
  C) Pb${}^{2+}$, Cl${}^{-}$
  D) Ag${}^{+}$, SO${}_4^{2-}$
  Show Answer
  The correct answer is C .
• Question 37: Ethanol reacts with aqueous sodium mono-oxoio date (l) to give a bright yellow solid with a characteristic smell. The product is? Options:
  A) trichloromethane
  B) triodomethane
  C) iodoethane
  D) ethanal
  Show Answer
  The correct answer is B .
• Question 38: 25cm³ of a 0.2 mol dm³ solution of Na₂CO₃ requires 20 cm³ of a solution of HCl for neutralization. The concentration of the HCl solution is Options:
  A) 0.5 mol dm³
  B) 0.6 mol dm³
  C) 0.2 mol dm³
  D) 0.4 mol dm³
  Show Answer
  The correct answer is A .
• Question 39:

  How many electrons will be found in the nucleus of an atom with mass number 23 and 17 neutrons?

  Options:
  A) none
  B) 6
  C) 7
  D) 8
  Show Answer
  The correct answer is A .
• Question 40:

  

  The I.U.P.A.C name for the compound is

  Options:
  A) isopropylethene
  B) acetylene
  C) 3- methylbutane
  D) 2-methylbutane
  E) 5-methylpentane
  Show Answer
  The correct answer is D .