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 1411:

  Two equal bulbs, one containing ammonia and the other nitrogen are opened mouth-to-mouth to each other at room temperature. The entropy in the mixture of gases is likely to

  Options:
  A) remain unchanged
  B) increase
  C) decrease
  D) change
  Show Answer
  The correct answer is B .
• Question 1412: Which of the following will produce a solution with pH less than 7 at equivalent point? Options:
  A) HNO ₃ +NaOH
  B) H ₂SO ₄ + KOH
  C) HC +Mg (OH) ₂
  D) HNO ₃ + KOH
  Show Answer
  The correct answer is C .
• Question 1413: Tin is unaffected by air at ordinary temperature due to its Options:
  A) Low melting point
  B) Weak electropositive character
  C) High boiling point
  D) White lustrous appearance
  Show Answer
  The correct answer is A .
• Question 1414: Copper is displaced from the solution of its salts by most metals because it Options:
  A) is a transition element
  B) is at the bottom of the activity series
  C) is very reactive
  D) has completely filled 3d-orbitals
  Show Answer
  The correct answer is B .
• Question 1415:

  Which of the following salts when dissolved in water will NOT give the corresponding pH value?

  Options:
  A) NaHSO₄, pH < 5
  B) Na₂CO₃, pH > 8
  C) Na₂Cl,pH = 7
  D) NaHCO, pH < 6
  Show Answer
  The correct answer is D .
• Question 1416: Two atoms represented as U and U are? Options:
  A) isomers
  B) allotropes
  C) isotopes
  D) anomers
  Show Answer
  The correct answer is C .
• Question 1417: Which of these salts will produce its metal, oxygen and nitrogen (IV) oxide on heating? Options:
  A) Silver and trioxonitrate (V)
  B) Sodium trioxonitrate (V)
  C) Calcium trioxonitrate (V)
  D) Lithium trioxonitrate (V)
  Show Answer
  The correct answer is A .
• Question 1418: Which of the following is physical change? Options:
  A) Burning kerosene
  B) Freezing ice cream
  C) Exposing white phosphorus
  D) Dissolving calcium in water
  Show Answer
  The correct answer is B .
• Question 1419:

  A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?

  [ M = 27, Cl = 35.5]

  Options:
  A) MCl
  B) MCl${}_2$
  C) MCl${}_3$
  D) M${}_2$Cl${}_6$
  Show Answer
  The correct answer is C .
• Question 1420: Which of the following compounds and elements would sublime on exposure to the atmosphere? Options:
  A) Ice
  B) Sulphur
  C) Phosphurous
  D) Iodine
  E) Potassium iodie
  Show Answer
  The correct answer is D .