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 1631: In which of the following reactions does reduction takes place Options:
  A) Fe²⁺ - e^- → Fe³⁺
  B) 2O^2- →O₂ + 4e^-
  C) Cr – 2e^- → Cr²⁺
  D) 2H⁺ + 2e^- → H₂
  Show Answer
  The correct answer is D .
• Question 1632: When iron is exposed to moist air, it gradually rusts. This is due to the formation of Options:
  A) hydrate iron (III) oxide
  B) anhydrous iron (III) oxide
  C) anhydrous iron (II) oxide
  D) hydrate iron (II) oxide
  Show Answer
  The correct answer is A .
• Question 1633: POlyvinyl chloride is used to produce Options:
  A) bread
  B) pencils
  C) ink
  D) pipes
  Show Answer
  The correct answer is D .
• Question 1634:

  Which of the following is a unique property of water compared to other liquids?

  Options:
  A) It is a poor solvent
  B) It does not evaporate
  C) It expands when freezing
  D) It has a low heat capacity
  Show Answer
  The correct answer is C .
• Question 1635:

  When heat is absorbed during a chemical reaction, the reaction is said to be

  Options:
  A) thermodynamic
  B) exothermic
  C) isothermal
  D) endothermic
  Show Answer
  The correct answer is D .
• Question 1636: Ammonia gas is normally dried with? Options:
  A) concentrated sulphuric acid
  B) quicklime
  C) anhydrous calcium chloride
  D) magnesium sulphate
  Show Answer
  The correct answer is B .
• Question 1637:

  If the molecular mass of tetraoxosulphate (VI) acid is 98, calculate its vapour density.

  Options:
  A) 196
  B) 49
  C) 106
  D) 82
  Show Answer
  The correct answer is B .
• Question 1638: What volume of oxygen will remain after reacting 8cm³ of hydrogen with 20cm³ of oxygen? Options:
  A) 10 cm³
  B) 12 cm³
  C) 14 cm³
  D) 16 cm³
  Show Answer
  The correct answer is D .
• Question 1639:

  The most important element on the earth's crust is?

  Options:
  A) Nitrogen
  B) Hydrogen
  C) Oxygen
  D) Fluorine
  Show Answer
  The correct answer is C .
• Question 1640: On heating anhydrous iron (ll) sulphate, in addition to producing iron (iii) oxide, which of the following is produced? Options:
  A) SO₂ (g) + FeS (s)
  B) SO₃ (g) +FeS(s)
  C) SO₂ (g) + SO₃(g)
  D) SO₂ (g) + H₂S (g)
  E) SO₃(g) + H₂S(g)
  Show Answer
  The correct answer is C .