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 1861: An organic compound containing 40.1% carbon and 6.6% hydrogen has an empirical formula of? Options:
  A) C₂H₄O₂
  B) C₂H₃O₂
  C) CH₂O
  D) CH₃O
  Show Answer
  The correct answer is C .
• Question 1862: The electronic configuration of an elements is 1s²2s²2p⁶3s²3p³. How many unpaired electrons are there in the element? Options:
  A) 5
  B) 4
  C) 3
  D) 2
  Show Answer
  The correct answer is C .
• Question 1863: As the concentration of an electrolyte reduces, the conductivity Options:
  A) reduces to zero
  B) decreases
  C) increase
  D) is unaffected
  Show Answer
  The correct answer is C .
• Question 1864: An emulsion may be produced by shaking a detergent solution with Options:
  A) palm wine
  B) ethanoic acid
  C) palm oil
  D) water
  Show Answer
  The correct answer is C .
• Question 1865: The product of the electrolysis of dilute sodium hydroxide using platinum electrodes are Options:
  A) Hydrogen and oxygen gases
  B) Water and hydrogen gas
  C) Water and sodium metal
  D) Sodium metal and oxygen gas
  Show Answer
  The correct answer is A .
• Question 1866: Cathode rays cause an object placed behind a perforated anode to cast a shadow on the screen. This observation shows that the rays Options:
  A) are positively charged
  B) are negatively charged
  C) Have mass
  D) travel in straight lines
  Show Answer
  The correct answer is D .
• Question 1867: Fermentation is the Options:
  A) breaking down of carbohydrate to glucose
  B) conversion of sugar to alcohol in the presence of yeast
  C) breaking down of sugar to carbohydrate
  D) conversion of alcohol to sugar in the presence of yeast
  Show Answer
  The correct answer is B .
• Question 1868: Which of the following substances is not a salt? Options:
  A) Aluminium oxide
  B) Sodium hydrogentrioxosulphate (V)
  C) Sodium trioxocarbonate (V)
  D) Zinc chloride
  Show Answer
  The correct answer is A .
• Question 1869:

  Which of the following represents the kind of bonding present in ammonium chloride?

  Options:
  A) ionic only
  B) covalent only
  C) ionic and dative covalent
  D) dative covalent
  Show Answer
  The correct answer is C .
• Question 1870: 2.0g of a monobasic acid was made up to 250 cm³ with distilled water. 25.00 cm³ of this solution required 20.00cm³ of 0.1 M NaOH solution for complete neutralization. The molar mass of the acid is? Options:
  A) 200 g
  B) 160 g
  C) 100 g
  D) 50 g
  Show Answer
  The correct answer is C .