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 831:

  The following non-metal form acidic oxides with oxygen except?

  Options:
  A) phosphorus
  B) sulphur
  C) carbon
  D) chlorine
  Show Answer
  The correct answer is C .
• Question 832: An insoluble salt can be prepared by Options:
  A) the reaction of trioxocarbonate (V) with an acid
  B) double decomposition
  C) the action of dilute acid on an insoluble base
  D) the reaction of metals with an acid
  Show Answer
  The correct answer is B .
• Question 833: The correct order of increasing boiling points of the following compounds C₃H₇OH, C₇H₁₆ and C₄H₁₀ is Options:
  A) C₃H₇OH → C₄H₁₀ → C₇H₁₀
  B) C₄H₁₀ → C₇H₁₆ → C₃H₇OH
  C) C₇H₁₆ → C₃H₇OH → C₄H₁₀
  D) C₄H₁₀ → C₃H₇OH → C₇H₁₆
  Show Answer
  The correct answer is D .
• Question 834: In a flame test for calcium, the flame appears Options:
  A) green when viewed through a blue glass
  B) blue when viewed through a blue glass
  C) orange -red when viewed through a blue glass
  D) brick-red when viewed through a blue-glass
  Show Answer
  The correct answer is D .
• Question 835: The Avogadro number of 24g of magnesium is the same as that of Options:
  A) 1g of hydrogen molecules
  B) 16g of oxygen molecules
  C) 32g of oxygen molecules
  D) 35.5g of chlorine molecules
  Show Answer
  The correct answer is C .
• Question 836: The major and most effective way of controlling pollution is to Options:
  A) improve machinery so that the substances released from combustion are less harmful
  B) pass strict laws against it by individuals and companies
  C) educate people on the causes and effects of pollution
  D) convert chemical wastes to harmless substances before releasing them into the environment
  Show Answer
  The correct answer is C .
• Question 837: When platinum electrodes are used during the electrolysis of copper (ll) tetraoxosulphate (lV) solution, the solution gets progressively? Options:
  A) acidic
  B) basic
  C) neutral
  D) amphoteric
  Show Answer
  The correct answer is A .
• Question 838: What reaction takes place when palm-oil is added to potash and foam are observed? Options:
  A) Neutralization
  B) Saponification
  C) Esterification
  D) Salting-out
  Show Answer
  The correct answer is B .
• Question 839: The basic assumption in the kinetic theory of gases that the collisions of the gaseous molecules are perfectly elastic implies that the Options:
  A) forces of attraction and repulsion are in equilibrium
  B) gaseous molecules can occupy any available space
  C) gaseous molecules will continue their motion indefinitely
  D) gases can be compressed
  Show Answer
  The correct answer is C .
• Question 840:

  A gas occupies a volume of 1.5 liters at a pressure of 2 atmospheres. If the pressure is increased to 4 atmospheres while the temperature remains constant, what will be the new volume of the gas?

  Options:
  A) 6 liters
  B) 1.5 liters
  C) 0.75 liters
  D) 3 liters
  Show Answer
  The correct answer is C .