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:

  Hard water is water with high concentrations of dissolved ions, in particular calcium and

  Options:
  A) magnesium ions
  B) nitrogen ions
  C) phosporus ions
  D) helium ions
  Show Answer
  The correct answer is A .
• Question 242: In order to remove one electron from a 3S orbital of gaseous sodium atom, about 496KJMol^-1 of energy is required. This energy is referred to as Options:
  A) electron affinity
  B) ionization energy
  C) activation evergy
  D) electronegativity
  Show Answer
  The correct answer is B .
• Question 243:

  An organic compound which decolorizes bromine water is likely to be?

  Options:
  A) C${}_3$H${}_8$
  B) C${}_2$H${}_6$
  C) C${}_4$H${}_{1}0$
  D) C${}_2$H${}_4$
  Show Answer
  The correct answer is D .
• Question 244:

  The Consecutive members of an alkane homologous series differ by

  Options:
  A) CH
  B) CH${}_2$
  C) CH${}_3$
  D) C${}_n$H${}_n$
  Show Answer
  The correct answer is B .
• Question 245: In the reaction NH₃ + H⁺ → NH₄⁺, the bond formed results from? Options:
  A) an electron transferred from NH₃ + H⁺
  B) an electron pair donated by NH₃
  C) an electron pair equally shared
  D) an electron pair donated by H⁺
  E) an electron tarnsferred from H⁺ to NH₃
  Show Answer
  The correct answer is B .
• Question 246:

  Methane is prepared in the laboratory by heating a mixture of sodium ethanoate with soda lime. The chemical constituent(s) of soda lime is/are

  Options:
  A) Ca(OH)${}_2$ and NaOH
  B) Na${}_2$CO${}_3$
  C) NaCl
  D) NaOH
  Show Answer
  The correct answer is A .
• Question 247: The process of converting linear alkanes to branched chain and cyclic hydrocarbons by heating in the presence of a catalyst to improve the quality of petrol is referred to as Options:
  A) refining
  B) craching
  C) reforming
  D) blending
  Show Answer
  The correct answer is C .
• Question 248: The ability of carbon to form long chains is referred to as Options:
  A) Alkylation
  B) Acylation
  C) Carbonation
  D) Catenation
  Show Answer
  The correct answer is D .
• Question 249: If 10.8 g of silver is deposited in a silver coulometer volume of oxygen liberated is? Options:
  A) 0.56 dm³
  B) 5.60 dm³
  C) 11.20 dm³
  D) 22.40 dm³
  Show Answer
  The correct answer is A .
• Question 250:

  Na${}_2$CO${}_3$ + 2HCl $\to$ 2NaCl + H${}_2$O + CO${}_2$

  The indicator most suitable for this reaction should have a pH equal to

  Options:
  A) 5
  B) 7
  C) 3
  D) 9
  Show Answer
  The correct answer is C .