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 211: An oxidation state of or in K2CrO7 Options:
  A) 7
  B) 6
  C) 5
  D) 4
  Show Answer
  The correct answer is B .
• Question 212: CHCl₃ + Cl₂ → HCl + CCl₄. The reaction above is an example of? Options:
  A) an addition reaction
  B) a substitution reaction
  C) a chlorination reaction
  D) a condensation reaction
  Show Answer
  The correct answer is B .
• Question 213: Which of the activities is commonly used as a nuclear fuel Options:
  A) uranium
  B) palladium
  C) actium
  D) thorium
  Show Answer
  The correct answer is A .
• Question 214:

  

  For which salt in the graph above does the solubility increase most rapidly with rise in temperature?

  Options:
  A) CaSO₄
  B) KNO₃
  C) NaCl
  D) KCl
  Show Answer
  The correct answer is B .
• Question 215: Which of the following compounds can be represented by the molecular formula C₂H₆O? Options:
  A) Propanel
  B) Ethanol
  C) Methanoic acid
  D) Glucose
  Show Answer
  The correct answer is B .
• Question 216: Which of the following salts can be melted without decomposition? Options:
  A) Na₂CO₃
  B) CaCO₃
  C) MgCO₃
  D) ZnCO₃
  Show Answer
  The correct answer is A .
• Question 217:

  200cm${}^3$ of 0.50mol/dm${}^3$ solution of calcium hydrogen trioxocarbonate (IV) is heated. The maximum weight of solid precipitated is

  Options:
  A) 10g
  B) 25g
  C) 20g
  D) 15g
  Show Answer
  The correct answer is A .
• Question 218: Some metals are extracted from their ores after some preliminary treatments by electrolysis (L), some of both processes (TL). Which set-up in the following for the extraction of ion, copper and aluminium is correct? Options:
  A) lron (L), copper (L) aluminium (T)
  B) lron (T) copper (L) aluminium (T)
  C) lron (TL) copper (TL) aluminium (TL)
  D) Iron (L) copper (T) aluminium (T)
  E) lron (T) copper (L), aluminium (TL)
  Show Answer
  The correct answer is E .
• Question 219: When chlorine gas is passed into a solution of sulphur dioxide? Options:
  A) sulphur dioxide is reduced to sulphur
  B) the chlorine is oxidized to hydrochloric acid
  C) dilute sulphuric acid and hydrochloric acid are produced
  D) Hydrochloric acid and sulphur are produced
  E) sulphur trioxide is the only product
  Show Answer
  The correct answer is C .
• Question 220: A compound gives an orange-red colour to non-luminous flame. This compound is likely to contain Options:
  A) Na⁺
  B) Ca²⁺
  C) Fe³⁺
  D) Fe²⁺
  Show Answer
  The correct answer is B .