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 1041: Which of the following represents a precipitation reaction? Options:
  A) H₂SO₄ + NaCl $\to$ NaHSO₄ + HCl
  B) Fe +H₂SO₄ $\to$ FeSO₄ + H₂
  C) 4HCl + MnO₂ $\to$ MnCl₂ + 2H₂O + Cl₂
  D) Na₂SO₄ + pb(NO₃) $\to$ PbSO₄ + 2NaNO
  E) CuO +2HCl $\to$ Cl₂ + H₂O
  Show Answer
  The correct answer is D .
• Question 1042: Which of the following chloride would exhibit the least ionic character? Options:
  A) MgCl₂
  B) CaCl₂
  C) LiCl
  D) AlCl₃
  Show Answer
  The correct answer is D .
• Question 1043:

  The following are isoelectronic ions except

  Options:
  A) Na${}^{+}$
  B) Mg${}^{2+}$
  C) Si${}^{2+}$
  D) O${}^{2+}$
  Show Answer
  The correct answer is C .
• Question 1044:

  Which of the following compounds is an example of an electrovalent bond?

  Options:
  A) NaCl (sodium chloride)
  B) CO2 (carbon dioxide)
  C) H2O (water)
  D) CH4 (methane)
  Show Answer
  The correct answer is A .
• Question 1045:

  

  The diagram above best illustrates the effect of decrease in

  Options:
  A) concentration
  B) temperature
  C) surface area
  D) pressure
  Show Answer
  The correct answer is A .
• Question 1046:

  Addition of sodium chloride to water to form a solution would lead to?

  Options:
  A) increase in freezing point and increase the boiling point
  B) increase in freezing point and decrease the boiling point
  C) decrease in freezing point and decrease the boiling point
  D) decrease in freezing point and increase the boiling point
  Show Answer
  The correct answer is D .
• Question 1047: A jet plane carrying 3,000 kg of ethane burns off all the gas forming water and carbondioxide. if all the carbondioxide is expelled and all the water formed is condensed and kept on board the plane, then the gain in weight is Options:
  A) 1,800 kg
  B) 900 kg
  C) 600 kg
  D) 2, 400 kg
  E) 1, 200 kg
  Show Answer
  The correct answer is D .
• Question 1048: The radioactive emission with the least ionization power is Options:
  A) $\alpha -particles$
  B) X-rays
  C) $\gamma -rays$
  D) $\beta -rays$
  Show Answer
  The correct answer is C .
• Question 1049: According to Charle's law, the volume of a gas becomes zero at Options:
  A) −100°c
  B) −273°c
  C) −373°c
  D) 0°c
  Show Answer
  The correct answer is B .
• Question 1050: The pollution from petroleum spillage in rivers and lakes can best be dispersed by Options:
  A) Pouring detergents
  B) Passing of ships through the area
  C) Pouring organic solvents
  D) Evaporation
  Show Answer
  The correct answer is A .