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 241:

  Which of the following represents the kind of bonding present in ammonium chloride?

  Options:
  A) ionic only
  B) covalent only
  C) ionic and dative covalent
  D) dative covalent
  Show Answer
  The correct answer is C .
• Question 242: The atomic numbers of two elements X and Y are 12 and 19 respectively. The bond of these two elements is? Options:
  A) ionic
  B) covalent
  C) neutral
  D) co-ordinate
  Show Answer
  The correct answer is B .
• Question 243: If the electron configuration of a element is p1s² 2s² 2P⁵, how many unpaired electron are there? Options:
  A) 2
  B) 8
  C) 1
  D) 4
  Show Answer
  The correct answer is C .
• Question 244: The role of sodium chloride in the preparation of soap is to? Options:
  A) purify the soap
  B) separate the soap from glycerol
  C) accelerate the decomposition of the fat or oil
  D) react with glycerol
  Show Answer
  The correct answer is B .
• Question 245:

  

  Changes in the physical in the scheme above.The letter X,Y and Z respectively represent

  Options:
  A) sublimation, condensation and freezing
  B) sublimation, vapourization and solidification
  C) freezing, condensation and sublimation
  D) evaporation, liquefaction and solidification
  Show Answer
  The correct answer is A .
• Question 246: The general formula of an alkyl halide (which represent the halide) is? Options:
  A) C_nH_2n - ₂X
  B) C_nH_2n + ₁X
  C) C_nH_2n + ₂X
  D) C_nH_2nX
  E) C_nH_2n - 1
  Show Answer
  The correct answer is B .
• Question 247: The colour of methyl orange in alkaline medium is Options:
  A) yellow
  B) pink
  C) orange
  D) red
  Show Answer
  The correct answer is A .
• Question 248:

  The products of the thermal decomposition of ammonium trioxonitrate(v) are?

  Options:
  A) Nitrogen (I) Oxide and Water
  B) Ammonia and Oxide
  C) Nitrogen and Water
  D) Nitrogen (IV) Oxide and Water
  Show Answer
  The correct answer is A .
• Question 249:

  Four elements P, Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively. Which of these elements is noble gas? 

  Options:
  A) P
  B) Q
  C) R
  D) S
  Show Answer
  The correct answer is B .
• Question 250:

  If the heat of combustion of hydrogen is -285.8kJ,

  What is the heat of formation of water?

  Options:
  A) +571.6 kJ
  B) -571.6 kJ
  C) -285.8 kJ
  D) +285.8 kJ
  Show Answer
  The correct answer is C .