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 891:

  Which of the following are mixtures? 

  I. Petroleum 

  II. Rubber latex 

  III. Vulcanizer's solution 

  IV. Carbon sulphide

  Options:
  A) I, II and III
  B) I, II and IV
  C) I and II only
  D) I and IV
  Show Answer
  The correct answer is A .
• Question 892: What is observed when aqueous solutions of each of tetraoxosulphate (VI) acid, potassium trioxoiodate (V) and potassium iodide are mixed together? Options:
  A) A white precipitate is formed
  B) A green precipitate is formed
  C) The mixture remains colourless
  D) The mixture turns reddish brown
  Show Answer
  The correct answer is D .
• Question 893:

  Calculate the percentage by mass of nitrogen in calcium trioxonitrate (V).
  [Ca = 40, N = 14, O = 16]

  Options:
  A) 8.5%
  B) 13.1%
  C) 17.1%
  D) 27.6%
  Show Answer
  The correct answer is C .
• Question 894: Coffee stains can best be removed by Options:
  A) Kerosine
  B) turpentine
  C) a solution of borax in water
  D) ammonia solution
  Show Answer
  The correct answer is C .
• Question 895:

  Which of the following is a set of neutral oxides?

  Options:
  A) N${}_2$O, H${}_2$O, CO
  B) N${}_2$O, SO${}_2$, CO
  C) N${}_2$O, Na${}_2$O, ZnO
  D) N${}_2$O, SO${}_3$, NO
  Show Answer
  The correct answer is A .
• Question 896: Which of the following metals is the least reactive? Options:
  A) Pb
  B) Sn
  C) Hg
  D) Au
  Show Answer
  The correct answer is D .
• Question 897: The pressure on 100 cm³ of oxygen gas at 35°C is 750mm of Hg.What would be the volume of the gas if the pressure is increased to 1000mm of Hg without changing the temperature? Options:
  A) 133.3 cm³
  B) 85 cm³
  C) 75 cm³
  D) 65 cm³
  E) 58.3 cm³
  Show Answer
  The correct answer is C .
• Question 898: The most suitable metal that can be used as lightning conductor is Options:
  A) silver
  B) copper
  C) iron
  D) aluminium
  Show Answer
  The correct answer is B .
• Question 899: Incomplete oxidation of ethanol yields Options:
  A) CH₃COOH
  B) CH₃COCH₃
  C) CH₃CH₂OCH₂CH₃
  D) CH₂CHO
  Show Answer
  The correct answer is D .
• Question 900: Which of these solutions will give a white precipitate with a solution of barium chloride acidified with hydrochloric acid? Options:
  A) Sodium trioxocarbonate (IV)
  B) Sodium tetraoxosulphate (IV)
  C) Sodium trioxosulphate (IV)
  D) Sodium sulphide
  Show Answer
  The correct answer is A .