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: How many hydrogen atoms does a single ring cycloalkane have less than the corresponding open-chain alkane? Options:
  A) Two
  B) Three
  C) Four
  D) One
  Show Answer
  The correct answer is A .
• Question 242: Which of the following pollutants is associated with brain damage? Options:
  A) Carbon (ll) oxide
  B) Radioactive fallout
  C) Biodegradable waste
  D) Sulphus (lV) oxide
  Show Answer
  The correct answer is A .
• Question 243:

  

  Use the table above to answer this question. The element that is likely to participate in covalent rather than ionic bonding is

  Options:
  A) Z
  B) Y
  C) X
  D) W
  Show Answer
  The correct answer is C .
• Question 244: The radioisotope used in industrial radiography for the rapid checking of faults in welds and casting is Options:
  A) carbon-14
  B) phosphorus-32
  C) cobalt-60
  D) iodine-131
  Show Answer
  The correct answer is C .
• Question 245: The temperature of a body decreases when drops of liquid placed on it evaporate because? Options:
  A) the atmospheric vapour pressure has a cooling effect on the body
  B) a temperature gradient exists between the drops of liquid and the body causing the latter to vaporate
  C) the heat of vapourization is drawn from the body causing it to cool
  D) the random motion of the liquid molecules causes a cooling effect on the body
  Show Answer
  The correct answer is C .
• Question 246:

  Aluminum hydroxide is used in the dyeing industry as a?

  Options:
  A) Dye
  B) Dispersant
  C) Salt
  D) Mordant
  Show Answer
  The correct answer is D .
• Question 247: Sulphur exists in six forms in the solid state. This property is known as? Options:
  A) isomerism
  B) allotropy
  C) isotopy
  D) isomorphism
  Show Answer
  The correct answer is B .
• Question 248:

  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 .
• Question 249:

  An organic compound X has the following properties:
  I. It is not miscible with water.
  ll. It has boiling point of 77^oC.
  lll. It has a sweet odour.
  IV. lt is insoluble in sodium hydrogen carbonate solution.
  V lt does not decolourize bromine water.
  X is therefore

  Options:
  A) methane
  B) ethanoic acid
  C) ethene
  D) ethyl ethanoate
  E) carbon tetrachloride
  Show Answer
  The correct answer is D .
• Question 250:

  Which of the following substances is NOT hygroscopic?

  Options:
  A) Salt
  B) Sugar
  C) Silica gel
  D) Aluminum
  Show Answer
  The correct answer is D .