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 41:

  The shapes of water, ammonia, carbon (iv) oxide and methane are respectively

  Options:
  A) linear, tetrahedral, angular and pyramidal
  B) angular, pyramidal, linear and tetrahedral
  C) pyramidal, linear, tetrahedral and angular
  D) tetrahedral, angular, pyramidal and linear
  Show Answer
  The correct answer is B .
• Question 42:

  When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;

  Options:
  A) nitrogen and carbondioxide
  B) the rare gases
  C) nitrogen and oxygen
  D) nitrogen and the rare gases
  Show Answer
  The correct answer is D .
• Question 43:

  Which process(es) is/are involved in the turning of starch iodide paper blue-black by chlorine gas?

  Options:
  A) chlorine attacks the starch to give the blue-black color
  B) chlorine attacks the iodide ion to give the blue-black color
  C) chlorine oxidizes the iodide ion to produce iodine which attacks the starch to give the blue-black color
  D) iodine attacks the starch to give the blue-black color
  Show Answer
  The correct answer is C .
• Question 44: Which of the following is a neutralization reaction? Addition of Options:
  A) nitric acid to hydrochloric acid
  B) nitric acid to sulphuric acid
  C) nitric acid to distilled water
  D) nitric acid to sodium hydroxide
  E) sodium chloride to distilled water
  Show Answer
  The correct answer is D .
• Question 45:

  What is the mass (in grams) of 500 mL of ethanol? (density of ethanol = 0.789 g/mL)

  Options:
  A) 394.5 mL
  B) 500 mL
  C) 394.5 g
  D) 500 g
  Show Answer
  The correct answer is C .
• Question 46:

  2X_(aq) + MnO_2(s) + 4H⁺_(aq) → X_2(g) + Mn²⁺_(aq) + 2H₂O.

  The reaction above can be used for the laboratory preparation of all halogens except fluorine because it is?

  Options:
  A) a poisionous gas
  B) an oxidizing agent
  C) electronegative in nature
  D) highly reactive
  Show Answer
  The correct answer is D .
• Question 47: Which of the following compounds gives a yellow residue when heated and also reacts with aqueous sodium hydroxide to give a white gelatinous precipitate soluble in excess sodium hydroxide solution? Options:
  A) (NH₄)CO₃
  B) ZnCO₃
  C) Al₂(SO₄)₃
  D) PbCO3
  Show Answer
  The correct answer is B .
• Question 48:

  A small quantity of solid ammonium chloride (NH₄Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone

  Options:
  A) distillation
  B) sublimation
  C) precipitation
  D) evaporation
  E) decomposition
  Show Answer
  The correct answer is B .
• Question 49: Which of the following statements applies during the electroysis of sodium hydroxide sodium hydroxide solution using platinum electrodes? Options:
  A) Na⁺ ions are discharged at the cathode
  B) Hydrogen ions are discharged at the anode
  C) the concentration of sodium hydroxide decrease at both electrode compartments
  D) the concentration of sodium hydroxide increases at the cathode only
  E) the concentration of sodium hydroxide increases at the anode only
  Show Answer
  The correct answer is D .
• Question 50: The carbon atoms on ethane are Options:
  A) sp² hybridized
  B) sp³ hybridized
  C) sp⁴ hybridized
  D) sp hybridized
  Show Answer
  The correct answer is B .