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 691: When a salt loses its water of crystallization to the atmosphere on exposure, the process is said to be Options:
  A) Efflorescence
  B) Deliquescence
  C) Effervescence
  D) Fluorescence
  Show Answer
  The correct answer is A .
• Question 692: Chlorine gas turns damp starch-iodide paper Options:
  A) pink
  B) colourless
  C) red
  D) dark blue
  Show Answer
  The correct answer is D .
• Question 693: The salt formed from strong acid and a strong base is Options:
  A) complex
  B) neutral
  C) basic
  D) acidic
  Show Answer
  The correct answer is B .
• Question 694:

  Which of the following gases contains the least number of atoms at s.t.p?

  Options:
  A) 1 mole of butane
  B) 4 moles of chlorine
  C) 3 moles of ozone
  D) 7 moles of argon
  Show Answer
  The correct answer is A .
• Question 695:

  A basic postulate of the kinetic theory of gases is that the molecules of a gas move in straight lines between collisions. This implies that

  Options:
  A) collisions are perfectly elastic
  B) forces of repulsion exist
  C) forces of repulsion and attraction are in equilibrium
  D) collisions are inelastic
  Show Answer
  The correct answer is B .
• Question 696: A change in the temperature of a saturated solution disturbs the equilibrium between the Options:
  A) Undissolved solute and the solvent
  B) Dissolved solute and the solvent
  C) Dissolved solute and the undissolved solute
  D) Dissolved solute and the solution
  Show Answer
  The correct answer is C .
• Question 697:

  The electronic configuration of an element is 1S${}^2$ 2S${}^2$ 2P${}^6$ 3S${}^2$ 3P${}^3$. How many unpaired electrons are there in the element?

  Options:
  A) 5
  B) 4
  C) 3
  D) 2
  Show Answer
  The correct answer is C .
• Question 698:

  The process of rusting is an example of the formation of

  Options:
  A) Basic oxide
  B) Acidic oxide
  C) Reducing oxide
  D) Amphoteric oxide
  Show Answer
  The correct answer is A .
• Question 699:

  An organic compound which liberate carbon(iv)oxide from trioxocarbonate(iv) solution is likely to be?

  Options:
  A) C${}_2$H${}_5$OH
  B) C${}_3$H${}_4$
  C) C${}_6$H${}_6$
  D) CH${}_3$COOH
  Show Answer
  The correct answer is D .
• Question 700: An emulsion paint consists of ? Options:
  A) gas or liquid particles dispersed in liguid
  B) liquid particles dispersed in liquid
  C) solid particles dispersed in liquid
  D) solid particles dispersed in solid
  Show Answer
  The correct answer is B .