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 791:

  2X_(aq) + MnO_2(s) + 4H⁺_(aq) → X_2(g) + Mn²⁺_(aq) + 2H₂O.

  The reaction above can be used for the laboratory preparation of all halogens except fluorine because it is?

  Options:
  A) a poisionous gas
  B) an oxidizing agent
  C) electronegative in nature
  D) highly reactive
  Show Answer
  The correct answer is D .
• Question 792:

  

  The set-up above would be useful for determining the amount of

  Options:
  A) oxygen in air
  B) water vapour in air
  C) CO₂ in air
  D) arygen in air
  Show Answer
  The correct answer is B .
• Question 793: Which of the following metals burns with brick red Options:
  A) Pb
  B) Ca
  C) Na
  D) Mg
  Show Answer
  The correct answer is B .
• Question 794:
  

  Use the section of the periodic table above to answer this question.

  Which of the indicate an alkali metal and a noble gas respectively?

  Options:
  A) M and E
  B) G and E
  C) R and L
  D) G and L
  Show Answer
  The correct answer is D .
• Question 795: The hydroxyl ion concentrated, (OH^-), in a solution of sodium hydroxide of pH 10.0 is? Options:
  A) 10^-10 mol dm^-3
  B) 10^-6 mol dm^-3
  C) 10^-4 mol dm^-3
  D) 10^-2 mol dm^-3
  Show Answer
  The correct answer is C .
• Question 796: Which of the following salts can be melted without decomposition? Options:
  A) Na₂CO₃
  B) CaCO₃
  C) MgCO₃
  D) ZnCO₃
  Show Answer
  The correct answer is A .
• Question 797:

  

  Which of the following compounds will take up the molecules of bromine?

  Options:
  A) l
  B) ll
  C) lll
  D) l and ll
  E) l and lll
  Show Answer
  The correct answer is B .
• Question 798: The type of isomerism shown by cis- and trans- isomers is Options:
  A) optical isomerism
  B) positional isomerism
  C) functional isomerism
  D) geometrical isomerism
  Show Answer
  The correct answer is D .
• Question 799:

  What is the percentage by mass of oxygen in Al₂(SO₄)₃. 2H₂O?

  [Al = 27, S = 32, H = 1, O = 16]

  Options:
  A) 14.29%
  B) 25.39%
  C) 50.79%
  D) 59.25%
  Show Answer
  The correct answer is D .
• Question 800:

  Which of the following alkaline metals react more quickly spontaneously with water?

  Options:
  A) Calcium
  B) Beryllium
  C) Magnesium
  D) Strontium
  Show Answer
  The correct answer is A .