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 2251: The compound produced when sodium peroxide is heated with excess sodium is Options:
  A) Na₂CO₃
  B) Na₂O
  C) NaNO₂
  D) NaOH
  Show Answer
  The correct answer is B .
• Question 2252: Chlorine, bromine and iodine resemble one another in that they Options:
  A) dissolve in alkalis
  B) react violently with hydorgen without heating
  C) are liquids
  D) displace one another from solutiions of their salts
  Show Answer
  The correct answer is D .
• Question 2253:

  200 cm³ of air was passed over heated copper in a syringe several times to produce copper (II) oxide.

  When cooled, the final volume of air recorded was 158cm³. Estimate the percentage of oxygen in the air?

  Options:
  A) 31%
  B) 27%
  C) 21%
  D) 19%
  Show Answer
  The correct answer is C .
• Question 2254: An element is electronegative if Options:
  A) it has a tendency to exist in the gaseous from
  B) its ions dissolve readily in water
  C) it has a tendency to lose electrons
  D) it has a tendency to gain electrons
  E) it readily froms covalent bonds
  Show Answer
  The correct answer is D .
• Question 2255: Oxidation is the process of? Options:
  A) gain of electrons
  B) loss of electrons
  C) gain of hydrogen
  D) loss of oxygen
  E) addition of an electropositive element to a substance
  Show Answer
  The correct answer is B .
• Question 2256:

  

  From the above diagram, the caustic soda in the conical flask serves to

  Options:
  A) dry ethene gas
  B) remove carbon (iv) oxides from ethene
  C) remove carbon (ii) oxide from ethene
  D) remove sulphur (iv) oxide from ethene
  Show Answer
  The correct answer is C .
• Question 2257: Calcium hydroxide and ammonium chloride when heated together will give an important product. This compound may be obtained dry by Options:
  A) dissolving it in water, recrystallizing it and then drying in the oven
  B) passing it through a concentrated aqueous solution of sodium hydroxide
  C) passing it through calcium oxide
  D) passing it through concentrated sulphuric acid
  E) passing it through anhydrous calcium choride
  Show Answer
  The correct answer is C .
• Question 2258: A major effect of oil pollution in coastal waters is the? Options:
  A) destruction of marine life
  B) desalination of the water
  C) increase in the acidity of the water
  D) detoxification of the water
  Show Answer
  The correct answer is C .
• Question 2259: Which of the following are the products of the reaction between CH₃COOH and CI₂ in sunlight? Options:
  A) CICH₂COOH + HCI
  B) CH₃COCI + HOCI
  C) CH₃COOCI + HCI
  D) CH₃COCI + HO₂
  Show Answer
  The correct answer is A .
• Question 2260:

  The most abundant rare gas in the atmosphere is?

  Options:
  A) He
  B) Ne
  C) Ar
  D) Xe
  Show Answer
  The correct answer is C .