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 841:

  

  The diagram above represents the formation of

  Options:
  A) a metallic bond
  B) an electrovalent bond
  C) a covalent bond
  D) a coordinate covalent bond
  Show Answer
  The correct answer is C .
• Question 842: Two elements, P and Q with atomic numbers 11 and 8 respectively , combine chemically to form the compound P_xQ_Y. The respective values of x and y are? Options:
  A) 1 and 1
  B) 1 and 2
  C) 2 and 1
  D) 3 and 1
  Show Answer
  The correct answer is C .
• Question 843:

  

  In the diagram above, Y is a mixture of

  Options:
  A) calcium hydroxide and ammonium chloride
  B) calcuim hydroxide and sodium chloride
  C) sodium chloride and ammonuim trioxonitrate (V)
  D) sodium dioxonitrate (lll) and ammouium chloride
  Show Answer
  The correct answer is A .
• Question 844: The number of isomers formed by C₆H₁₄ is Options:
  A) 4
  B) 5
  C) 2
  D) 3
  Show Answer
  The correct answer is B .
• Question 845: Which of the following statements is FALSE? Options:
  A) Copper (ll) ion can be reduced to copper (l) ion by hydrochloric acid and zinc
  B) Sodium metal dissolves in water giving oxygen
  C) Nitrogen is insoluble in water
  D) Carbondioxide is soluble in water
  E) lead has a higher atomic weight than copper
  Show Answer
  The correct answer is B .
• Question 846: Which of the following substances is not a salt? Options:
  A) Aluminium oxide
  B) Sodium hydrogentrioxosulphate (V)
  C) Sodium trioxocarbonate (V)
  D) Zinc chloride
  Show Answer
  The correct answer is A .
• Question 847: In the extraction of aluminum from purified bauxite by electrolysis, cryolite is used because Options:
  A) it makes bauxite a better conductor of electricity
  B) it makes bauxite melt at a lower temperature
  C) it makes aluminium purer
  D) it prevents aluminium from getting oxidized
  E) it protects the carbon electrodes used in the process
  Show Answer
  The correct answer is B .
• Question 848:

  Two cylinders A and B each contains 30 cm³ of

  Oxygen and nitrogen respectively at the same temperature and pressure. If there are 5.0 moles of nitrogen, then the mass of oxygen is?

  Options:
  A) 3.2 g
  B) 6.4 g
  C) 80.0 g
  D) 160.0 g
  Show Answer
  The correct answer is D .
• Question 849: The oxidation number of manganese in KMnO₄ is? Options:
  A) +1
  B) +3
  C) +5
  D) +7
  E) +2
  Show Answer
  The correct answer is D .
• Question 850:

  A secondary alkanol can be oxidized to give an

  Options:
  A) alkanone
  B) alkyne
  C) alkanoic acid
  D) alkanal
  Show Answer
  The correct answer is A .