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 611: Catalytic hydrogenation of benzene produces? Options:
  A) an aromatic hydrocarbon
  B) margarine
  C) cyclohexane
  D) D.D.T
  Show Answer
  The correct answer is C .
• Question 612: Which of the following substance is a mixture? Options:
  A) Granulated sugar
  B) Sea-water
  C) Sodium chloride
  D) Iron fillings
  Show Answer
  The correct answer is B .
• Question 613:

  2H₂S_(g) + SO_2(g) + H₂O_(l) → 3S_(s) + 3H₂O_(l)..........(I)

  3CuO_(s) + 2NH_3(g) → 3Cu_(s) + 3H₂O_(l) + N_2(g).........(II)

  In the equations above, the oxidizing agent (I) and the reducing agent in (II) respectively are?

  Options:
  A) H₂S and NH₃
  B) SO₂ and CuO
  C) SO₂ and NH₃
  D) H₂S and CuO
  Show Answer
  The correct answer is C .
• Question 614:

  Which of these alloys contains copper?

  Options:
  A) solder
  B) steel
  C) permallory
  D) bronze
  Show Answer
  The correct answer is D .
• Question 615: When dilute hydrochloric acid is added to iron(ll)sulphide, the gas evolved will? Options:
  A) turn moist red litmus paper blue
  B) turn lime water milky
  C) blacken lead acurate paper
  D) rekindle a glowing splint
  E) burn a sqeakly pop
  Show Answer
  The correct answer is C .
• Question 616: The catalyst used in the contact process for the manufacture of tetraoxosulphate (VI) acid is Options:
  A) manganes (IV) oxide
  B) manganese (ll) tetraoxosulphate (VI)
  C) vanadium (V) oxide
  D) iron metal
  Show Answer
  The correct answer is C .
• Question 617: On exposure to the atmosphere, a hydrated salt loses its water of crystallization to become anhydrous. This phenomenon is referred to as Options:
  A) efflorescence
  B) diliquescence
  C) hygroscopy
  D) hydrolysis
  Show Answer
  The correct answer is A .
• Question 618: Aluminium hydroxide is used in the dyeing industry as a Options:
  A) Salt
  B) Dye
  C) Mordant
  D) Dispersant
  Show Answer
  The correct answer is C .
• Question 619: Alloys are best prepared by Options:
  A) Electroplating
  B) Arc-welding
  C) Reducing and mixture of their metallic oxide
  D) Cooling a molten mixture of the metals
  Show Answer
  The correct answer is D .
• Question 620: To a solution of an unknown compound, a little dilute tetraoxosulphate (VI) acid was added with some freshly prepared iron (II) tetraoxosulphate (VI) solution. The brown ring observed after the addition of a stream of concentrated tetraoxosulphate (VI) acid confirmed the presence of Options:
  A) CO^-
  B) Cl^-
  C) SO^-
  D) NO
  Show Answer
  The correct answer is D .