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: A common characteristic shared by iron and aluminium is that both? Options:
  A) are extracted by reduction methods
  B) form only basic oxides
  C) show oxidation states of +2 and +3
  D) form soluble hydroxides
  Show Answer
  The correct answer is A .
• Question 612: If chlorine is bubbled into water and the resulting yellowish-green solution is exposed to bright sunlight for a while, the solution will decompose giving out Options:
  A) oxygen and leaving behind aqueous hydrochloric acid
  B) chlorine and oxygen
  C) oxygen, hydrogen and chlorine
  D) oxygen, thereby producing hypochlorous acid
  Show Answer
  The correct answer is A .
• Question 613:

  The number of electrons in the valence shell of an element of atomic number 14 is?

  Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is D .
• Question 614: The nucleus of the isotopes tritium contains Options:
  A) two neutrons with no protons
  B) one neutron and one proton
  C) two neutrons and one proton
  D) two neutrons, one proton and one electron
  Show Answer
  The correct answer is C .
• Question 615: The maximum number of electrons in the L shell of an atom is Options:
  A) 2
  B) 8
  C) 18
  D) 32
  Show Answer
  The correct answer is B .
• Question 616: Which of the following gases may not be dried with concentrated sulphuric acid? Options:
  A) HCl
  B) N₂
  C) Cl₂
  D) SO₂
  E) NH₃
  Show Answer
  The correct answer is E .
• Question 617:

  2-methylprop-1-ene is a structuralisomer of?

  Options:
  A) But-1-yne
  B) 2-methyl But-1-ene
  C) 3-methyl prop-1-yne
  D) But-2-ene
  Show Answer
  The correct answer is D .
• Question 618: Calculate the number of moles of HCl present in 20cm³ of a 0.75M solution of the acid Options:
  A) 0.015 mole
  B) 0.038 mole
  C) 3.800 moles
  D) 1.500 moles
  Show Answer
  The correct answer is A .
• Question 619:

  What volume of oxygen measured at s.t.p would be liberated on electrolysis by 9650 coulombs of electricity?

  (Molar volume of gas = 22.4 dm³, F = 96,500 C mol^-)

  Options:
  A) 22.4 dm³
  B) 11.2 dm³
  C) 1.12 dm³
  D) 0.560 dm³
  Show Answer
  The correct answer is D .
• Question 620: When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are; Options:
  A) nitrogen and carbondioxide
  B) the rare gases
  C) nitrogen and oxygen
  D) nitrogen and the rare gases
  E) nitrogen, carbondioxide and the rare gases
  Show Answer
  The correct answer is D .