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 1231: A gas that is not associated with global warming is Options:
  A) CO₂
  B) SO₃
  C) CH₄
  D) H₂
  Show Answer
  The correct answer is A .
• Question 1232: 100 cm³ of oxygen is made to react with 50 cm ³ of hydrogen, and the whole reaction mixture was then passed through anhydrous calcium chloride. What is the volume of gas left? Options:
  A) 5 cm³
  B) 25 cm³
  C) 50 cm³
  D) 75 cm³
  E) 100 cm³
  Show Answer
  The correct answer is D .
• Question 1233: The solvent used for removing grease stain is Options:
  A) turpentine
  B) ammonia solution
  C) ethanol
  D) solution of borax in water
  Show Answer
  The correct answer is B .
• Question 1234:

  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 1235: The addition of water to calcium oxide leads to? Options:
  A) a physical change
  B) a chemical change
  C) the formation of a mixture
  D) an endothermic change
  Show Answer
  The correct answer is B .
• Question 1236:

  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 1237: When H₂S gas is passed into a solution of iron (III) chloride, the colour changes from yellow to green. This is because? Options:
  A) H_(s)S is reduced to S
  B) Fe³⁺ ions are oxidized by H_(s)S
  C) Fe³⁺ ions are oxidized Fe³⁺ ions
  D) Fe³⁺ ions are reduced to Fe²⁺ ions
  Show Answer
  The correct answer is D .
• Question 1238: Which of the following is an electrolyte? Options:
  A) alcohol
  B) sodium ethanoate
  C) solid potassium hydroxide
  D) mercury
  Show Answer
  The correct answer is B .
• Question 1239:

  Which separation technique is used to separate different pigments in a mixture based on their affinity for a stationary phase and a mobile phase?

  Options:
  A) Chromatography
  B) Filtration
  C) Decantation
  D) Distillation
  Show Answer
  The correct answer is A .
• Question 1240: Pure solvents are obtained by Options:
  A) distillation
  B) condensation
  C) extraction
  D) evaporation
  E) desolution
  Show Answer
  The correct answer is A .