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 371: The fuming of kettles is caused by the presence in the water of Options:
  A) Calcium tetraoxosulphate (VI)
  B) Calcium hydrogentrioxocarbonate (IV)
  C) Calcium hydroxide
  D) Calcium trioxocarbonate (IV)
  Show Answer
  The correct answer is B .
• Question 372: Magnesium ribbon was added to each of the following aqueous solution in turn: H₂SO₄, AgNO₃, HNO₃, HCl, NH₃, HCl, NH₃. In which case does the magnesium become covered with a dark precipitate? Options:
  A) H₂SO₄
  B) AgNO₃
  C) HNO₃
  D) NH₃
  E) HCl
  Show Answer
  The correct answer is B .
• Question 373:

  Which of the following is an example of a chemical change?

  Options:
  A) dissolution of salt in water
  B) rusting of iron
  C) melting of ice
  D) separating a mixture by distillation
  Show Answer
  The correct answer is B .
• Question 374:

  An organic compound which decolorizes bromine water is likely to be?

  Options:
  A) C${}_3$H${}_8$
  B) C${}_2$H${}_6$
  C) C${}_4$H${}_{1}0$
  D) C${}_2$H${}_4$
  Show Answer
  The correct answer is D .
• Question 375: Which of the following statements is correct about the periodic table? Options:
  A) Elements in the same group have the same number of electron shells
  B) The non-metallic properties of the elements tend to decrease across each period
  C) Elements in the same period have the same number of valence electrons
  D) The valence electrons of the elements increase progressively across the period
  Show Answer
  The correct answer is D .
• Question 376: Sodium hydrogen should be stored in properly closed containers because it? Options:
  A) readily asborbs water vapour to air
  B) is easily oxidize by atmospheric oxygen
  C) turns golden yellow when exposed to light
  D) melts at a low temperature
  Show Answer
  The correct answer is A .
• Question 377:

  

  Choose the correct answer in the option above.

  Which of the following is a primary amine?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is B .
• Question 378: The decolourization of purple colour of tetraoxomanganate (VII) ion is a test for Options:
  A) alkenes
  B) alkanols
  C) alkanals
  D) alkanes
  Show Answer
  The correct answer is A .
• Question 379:

  

  Select the right answer from the structure above.Which of the following compounds represents the polymerization product of ethyne?

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is A .
• Question 380: Geometric isomerism can exist in Options:
  A) hex-3-ene
  B) hexane
  C) prop-l-ene
  D) 3-methyl but -l-ene
  Show Answer
  The correct answer is A .