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 1621:

  

  Use the diagram above to answer this question.

  The reaction taking place in the flask above is known as

  Options:
  A) hydrolysis
  B) double decomposition
  C) dehydration
  D) pyrolysis
  Show Answer
  The correct answer is C .
• Question 1622: The energy changes accompanying the addition of an electron to a gaseous atom is called? Options:
  A) first ionization energy
  B) second ionization energy
  C) electron affinity
  D) electronegativity
  Show Answer
  The correct answer is C .
• Question 1623: Argon is used in gas-filled electric lamp because it helps to? Options:
  A) prevent the reduction of the lamp fillaments
  B) prevent oxidation of the lamp fillaments
  C) make the lamp fillament glow brightly
  D) keep the atmosphere in the lamp inert
  Show Answer
  The correct answer is C .
• Question 1624: When chlorine Is passed into water and the resulting solution exposed to sunlight, the product formed are Options:
  A) Chlorine gas and hydrogen
  B) Oxygen and oxochlorate (I) acid
  C) Chlorine gas and oxochlorate (I) acid
  D) Hydrochloric acid and oxygen
  Show Answer
  The correct answer is D .
• Question 1625: Hypochlorous acid is used as a bleach because Options:
  A) it is a strong acid
  B) it yields chlorine readily in pure water
  C) it is an oxidising agent
  D) it is a weak acid
  E) it is a reducing agent
  Show Answer
  The correct answer is C .
• Question 1626: The phenomenon whereby sodium trioxocarbonate (IV) decahydrate loses some of its water of crystallization on exposure to the atmosphere is known as? Options:
  A) deliquescene
  B) hygroscopy
  C) effervescence
  D) efflorescence
  Show Answer
  The correct answer is D .
• Question 1627: Which of the following types of reactions takes place between C₂H₄ and the halogens? Options:
  A) Substitution
  B) Polymerization
  C) Addition
  D) Saponification
  E) Oxidation
  Show Answer
  The correct answer is C .
• Question 1628: If sulphur (IV) oxide and methane are released simultaneously at the opposite ends of a narrow tube, the rates of diffusion Rso₂ and Rch₄ will be in the ratio? (S = 32, O = 16, C = 12, H = 1) Options:
  A) 4:1
  B) 2:1
  C) 1:2
  D) 1:4
  Show Answer
  The correct answer is C .
• Question 1629: The most common ores of iron include Options:
  A) haematite, malachite and limonite
  B) chalcolite, calamine and bornite
  C) magnetite, haematite and bornite
  D) magnetite, chalcolite and bornite
  Show Answer
  The correct answer is C .
• Question 1630: Deliquescent substances are also? Options:
  A) efflorescent
  B) anhydrous
  C) hygroscopic
  D) insoluble
  Show Answer
  The correct answer is C .