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: Ordinary glass is manufactured from silica, CaCO₃ and Options:
  A) Na₂CO₃
  B) K₂CO₃
  C) K₂SO₄
  D) NaHCO₃
  Show Answer
  The correct answer is A .
• Question 32: The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is Options:
  A) Na₂SO₄
  B) Na₂SO₃
  C) Na₂S
  D) Na₂CO₃
  Show Answer
  The correct answer is B .
• Question 33:

  The general formula for the Alkanals is?

  Options:
  A) R${}_2$CO
  B) RCHO
  C) ROH
  D) RCOOR
  Show Answer
  The correct answer is B .
• Question 34: Cancerous growths are cured by exposure to Options:
  A) γ - rays
  B) β - rays
  C) α - rays
  D) x - ray
  Show Answer
  The correct answer is D .
• Question 35:

  Which of the following is the best starting material for the preparation of oxygen? Heating of trioxonitrate (v) with

  Options:
  A) Pb
  B) Zn
  C) Ca
  D) Na
  Show Answer
  The correct answer is A .
• Question 36:

  Suitable reagents for the laboratory preparation nitrogen are

  Options:
  A) sodium dioxonitrate(III) and ammonium chloride
  B) sodium trioxonitrate(V) and ammonium chloride
  C) sodium chloride and ammonium trioxonitrate(V)
  D) sodium chloride and ammonium di-ozonitrate(III)
  Show Answer
  The correct answer is A .
• Question 37: Polystyrene is widely used as packaging materials for fragile objects during transportation because of its Options:
  A) ligjtness
  B) low density
  C) high density
  D) high compressibility
  Show Answer
  The correct answer is D .
• Question 38: The compound produced when sodium peroxide is heated with excess sodium is Options:
  A) Na₂CO₃
  B) Na₂O
  C) NaNO₂
  D) NaOH
  Show Answer
  The correct answer is B .
• Question 39: One of the following techniques can be used to show that chlorophyll pigment is a mixture of chemical compounds and not a single coloured compound Options:
  A) cystallization
  B) hydrolysis
  C) sublimation
  D) filtration
  E) chromatography
  Show Answer
  The correct answer is E .
• Question 40: The atom of an element X is represented as ${}_z^{y}X$. The basic chemical properties of X depend on the value of Options:
  A) Y
  B) Z
  C) Y - Z
  D) Z - Y
  Show Answer
  The correct answer is B .