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 1011:

  When dilute aqueous solutions of lead (II) nitrate and potassium bromide are mixed, a precipitate is observed.

  The products of this reaction are?

  Options:
  A) PbO_(s) + Br^- + KNO₃
  B) Br₂ + NO_2(g) + PbBr_2(s)
  C) PbO_(s) + K⁺_(aq) + Br_(aq) + NO_2(g)
  D) PbBr_2(s) + K_(aq) + K⁺_(aq) + NO_3(aq)
  Show Answer
  The correct answer is D .
• Question 1012:

  Suitable reagents for the laboratory preparation nitrogen are

  Options:
  A) sodium dioxonitrate(III) and ammonium chloride
  B) sodium trioxonitrate(V) and ammonium chloride
  C) sodium chloride and ammonium trioxonitrate(V)
  D) sodium chloride and ammonium di-ozonitrate(III)
  Show Answer
  The correct answer is A .
• Question 1013:

  The general formula of alkanoates is?

  Options:
  A) $RCHO$
  B) $R_{2}CO$
  C) $RCOOH$
  D) $RCOO{R}^{\prime }$
  Show Answer
  The correct answer is D .
• Question 1014:

  During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment

  Options:
  A) the litmus turns blue but no gas is evolved
  B) the litmus turns blue and oxygen is evolved
  C) the litmus turns blue and hydrogen is evolved
  D) the litmus turns red and oxygen is evolved
  Show Answer
  The correct answer is D .
• Question 1015:

  When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes?

  Options:
  A) Bipolar
  B) Negatively charged
  C) Positively charged
  D) Neutral
  Show Answer
  The correct answer is B .
• Question 1016:

  Which type of salt is found in antacid medications and is used to relieve heartburn and indigestion?

  Options:
  A) Aluminum chloride
  B) Magnesium chloride
  C) Sodium chloride
  D) Calcium chloride
  Show Answer
  The correct answer is B .
• Question 1017:

  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 1018: The order in which a mixture of sand, ammonium chloride and sodium chloride can be separated is Options:
  A) dissolution → dryness → filtration → evaporation
  B) filtration → sublimation → evaporation → dryness
  C) sublimation → dissolution → filtration → evaporation
  D) dissolution → filtration → sublimation → evaporation
  Show Answer
  The correct answer is C .
• Question 1019: An anhydride is an oxide of non-mental? Options:
  A) which will not dissolve in water
  B) whose solution in water has a pH greater than 7
  C) whose solution in water has a pH less than 7
  D) whose solution in water has a pH of 7
  Show Answer
  The correct answer is C .
• Question 1020:

  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 .