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 1271:

  What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?

  Options:
  A) 24,125 C
  B) 48,250 C
  C) 72,375 C
  D) 96,500 C
  Show Answer
  The correct answer is B .
• Question 1272: The enzyme used in the hydrolysis of starch to dextrin and maltose is Options:
  A) Zymase
  B) Sucrase
  C) Amylase
  D) Lactase
  Show Answer
  The correct answer is C .
• Question 1273: 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 1274:

  

  The functional groups present in the compound above are

  Options:
  A) Alkene and halo-group
  B) Hydroxyl and chloro-group
  C) Alkene and chloro-group
  D) Hydroxyl and halo-group
  Show Answer
  The correct answer is B .
• Question 1275:

  

  The diagram above represents an atom of

  Options:
  A) magnesium
  B) helium
  C) chlorine
  D) neon
  Show Answer
  The correct answer is A .
• Question 1276: Which of the following compounds will give a precipitate with an aqueous ammoniacal solution of copper (l) chloride? Options:
  A) CH₃ = CHCH₃
  B) CH₃ ≡ CCH₃
  C) HC = C-CH₂CH₃
  D) CH₂ = CH-CH = CH₂
  Show Answer
  The correct answer is B .
• Question 1277: Calculate the amount in moles of silver deposited when 9650C of electricty is passed through a solution of silver salt [= 96500 Cmol^-1] Options:
  A) 0.05
  B) 10.80
  C) 10.00
  D) 0.10
  Show Answer
  The correct answer is D .
• Question 1278:

  The process by which salt and water reacted in a limited way to form an acid or abase is?

  Options:
  A) Neutral process
  B) Basic acidic process
  C) Hydrolysis
  D) Sublimation
  Show Answer
  The correct answer is C .
• Question 1279:

  

  The curve depicts titration between

  Options:
  A) Strong acid and strong base
  B) Strong acid and weak base
  C) Weak acid and weak base
  D) Weak acid and strong base
  Show Answer
  The correct answer is C .
• Question 1280: The nitrogen gas obtained by burning an excess of phosphorus in air has a density higher than the nitrogen from nitrogen compounds because the nitrogen from air is contaminated with? Options:
  A) some unburnt phosporus
  B) P₂O₅ vapour
  C) some oxygen
  D) rare gases
  E) carbondioxide
  Show Answer
  The correct answer is D .