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 2051:

  NH₃ + H₃O⁺

  → NH₄⁺ + H₂O. It may be deduced from the reaction above that?

  Options:
  A) a redox reaction has occurred
  B) H₃O⁺ acts as an oxidizing agent
  C) H₃O⁺ acts as an acid
  D) water acts as ab acid
  Show Answer
  The correct answer is C .
• Question 2052: An element X forms the following compounds with chlorine; XCl₄, XCl₃, XCl₂. This illustrates the Options:
  A) law of multiple proportions
  B) law of chemical proportions
  C) law of simple proportions
  D) law of conservation of mass
  E) law of definite proportions
  Show Answer
  The correct answer is A .
• Question 2053: Which of the following separation processes is most likely to yield high quality ethanol (>95%) from palm wine? Options:
  A) Fractional distillation without a dehydrant
  B) simple distillation with a dehydrant
  C) fractional distillation with a dehydrant
  D) column chromatography
  E) evaporation
  Show Answer
  The correct answer is C .
• Question 2054: When ΔH is negative, a reaction is said to be Options:
  A) endothermic
  B) exothermic
  C) reversible
  D) ionic
  Show Answer
  The correct answer is B .
• Question 2055: 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 2056: The gas that is most useful in protecting humans against solar marathon is Options:
  A) chlorine
  B) ozone
  C) carbon IV oxide
  D) hydrogen sulphur
  Show Answer
  The correct answer is B .
• Question 2057: Sodium chloride has no solubility product value because of its? Options:
  A) saline nature
  B) high solubility
  C) low solubility
  D) insolubility
  Show Answer
  The correct answer is B .
• Question 2058: Which of the following is a property of ionic chlorides? Options:
  A) They can be decomposed by heat
  B) They react with aqueous AgNO₃ to give a white precipiate which is soluble in excess ammonia
  C) They explode when in contact with dry ammonia
  D) They react with concentrated tetraoxosulphate (IV) acid to give white fumes of chlorine gas
  Show Answer
  The correct answer is B .
• Question 2059: Phosphorus is stored under water to prevent it from Options:
  A) Dehydrating
  B) Becoming inert
  C) Smelling
  D) Catching fire
  Show Answer
  The correct answer is D .
• Question 2060:

  2-methylprop-1-ene is a structuralisomer of?

  Options:
  A) But-1-yne
  B) 2-methyl But-1-ene
  C) 3-methyl prop-1-yne
  D) But-2-ene
  Show Answer
  The correct answer is D .