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 121:

  Methanoic acid mixes with water in all proportions and has about the same boiling point as water. Which of the following methods would you adopt to obtain pure water from a mixture of Sand, water and methanoic acid?

  Options:
  A) Fractional distillation
  B) Filtration followed by distillation
  C) Neutralization with sodium hydroxide followed by distillation
  D) Neutralization with sodium hydroxide followed by filtration
  Show Answer
  The correct answer is B .
• Question 122: The monomer of nylon is Options:
  A) Hydroxybenzene
  B) Hexanedioic acid
  C) Benzene -1,-4-dicarboxylic acid
  D) Ethane-1,2-diol
  Show Answer
  The correct answer is B .
• Question 123: The noble gases owe their inactivity to Options:
  A) Octet configuration
  B) Cyclic shape
  C) Hexagonal shape
  D) Obtuse configuration
  Show Answer
  The correct answer is A .
• Question 124:

  

  The I.U.P.A.C name for the compound

  Options:
  A) 2-chloro-isopentane
  B) 3-chloro-isopentane
  C) 2-chloro-2-methylbutane
  D) 1-chloro-2,2- dimethylpropane
  E) 2-chloro-2-ethylpropane
  Show Answer
  The correct answer is C .
• Question 125:

  

  Choose the correct option from the graph above.

  3Fe_(S) + 4H₂O_(g) ⇌ Fe₃O_4(s) + 4H_2(g). The equilibrium constant, K, of the reaction above is represented as

  Options:
  A) A
  B) B
  C) C
  D) D
  Show Answer
  The correct answer is C .
• Question 126: Rare gases are suitable because they Options:
  A) are monoatomic
  B) form ions easily
  C) have duplet or octet electronic configuration in the outermost shells in their atoms
  D) are volatile gases
  Show Answer
  The correct answer is C .
• Question 127:

  Elements X and Y have electronic configurations 1s${}^2$2s${}^2$2p${}^4$ and 1s${}^2$2s${}^2$2p${}^6$3s${}^2$3p${}^1$ respectively. When they combine, the formula of the compound formed is

  Options:
  A) XY
  B) X${}_2$Y
  C) Y${}_2$X${}_3$
  D) X${}_2$Y${}_3$
  Show Answer
  The correct answer is C .
• Question 128: If chlorine is bubbled into water and the resulting yellowish-green solution is exposed to bright sunlight for a while, the solution will decompose giving out Options:
  A) oxygen and leaving behind aqueous hydrochloric acid
  B) chlorine and oxygen
  C) oxygen, hydrogen and chlorine
  D) oxygen, thereby producing hypochlorous acid
  Show Answer
  The correct answer is A .
• Question 129: In the periodic table, what is the property that decreases along the periodic and increases down the group? Options:
  A) Atomic number
  B) Electron affinity
  C) Ionization potential
  D) Atomic radius
  Show Answer
  The correct answer is D .
• Question 130:

  An aqueous solution of a metal salt, M. gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia Therefore the cation in M is

  Options:
  A) Zn
  B) Ca
  C) Al
  D) Po
  Show Answer
  The correct answer is A .