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 1621: Which of the following statements is correct during the electrolysis of a caustic soda solution using platinum electrodes? Options:
  A) Oxygen gas is given off at the cathode
  B) Hydrogen gas is given of at the anode
  C) Sodium metals is deposited at the anode
  D) Sodium metal is deposited at the cathode
  E) AAlkalinity at the cathode increases
  Show Answer
  The correct answer is E .
• Question 1622:

  

  From the diagram above the mass of crystals deposited when 1 dm ³ of a saturated solution of NaCl is cooled from 80^oC to 60^oC is

  [Na = 23, Cl = 35.5]

  Options:
  A) 117.00 g
  B) 58.50 g
  C) 11.70 g
  D) 5.85 g
  Show Answer
  The correct answer is A .
• Question 1623: Which of the following will shift to the left from dilute tetraoxosulphate (VI) acid? Options:
  A) Lead
  B) Magnesium
  C) Cpper
  D) Gold
  Show Answer
  The correct answer is B .
• Question 1624: An increase in temperature causes an increase in the pressure of a gas because? Options:
  A) it decreases the number of collision between the molecules
  B) the molecules of the gas bombard the walls of the container more frequently
  C) it increases the number of collision between the molecules
  D) it causes the molecules to combine
  Show Answer
  The correct answer is C .
• Question 1625:

  

  In the shown experiment (Fig. 1) the litmus paper will initially

  Options:
  A) be bleached
  B) turn green
  C) turn red
  D) turn blue
  Show Answer
  The correct answer is D .
• Question 1626: An electron can be added to a halogen atom to form a halide ion with Options:
  A) 2 valence electrons
  B) 3 valence electrons
  C) 7 valence electrons
  D) 8 valence electrons
  Show Answer
  The correct answer is D .
• Question 1627:

  

  The two functional groups in the above compound are

  Options:
  A) alcohol and amine
  B) acid and amine
  C) aldehyde and acid
  D) ketone and amine
  Show Answer
  The correct answer is B .
• Question 1628: The role of sodium chloride in the preparation of soap is to? Options:
  A) purify the soap
  B) separate the soap from glycerol
  C) accelerate the decomposition of the fat or oil
  D) react with glycerol
  Show Answer
  The correct answer is B .
• Question 1629:

  By what amount must the temperature of 200cm${}^3$ of Nitrogen at 27°C be increased to double the pressure if the final volume is 150cm${}^3$ (Assume ideality)

  Options:
  A) 150°C
  B) 177°C
  C) 75°C
  D) 120°C
  Show Answer
  The correct answer is B .
• Question 1630: The haloalkanes used in dry-cleaning industries are Options:
  A) trichloromethane and tetrachloromethane
  B) chloroethene and dichloroethene
  C) trichloroethene and tetrachloroethene
  D) chloroethane and dichloroethene
  Show Answer
  The correct answer is A .