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 1521: In the electrolysis of brine the anode is Options:
  A) platinum
  B) copper
  C) zinc
  D) carbon
  Show Answer
  The correct answer is D .
• Question 1522:

  

  If in the graph above 1 dm³ of a saturated solution of KCL is cooled from 80^oC, the mass of crystals deposited will be  [K = 39, Cl = 35.5]

  Options:
  A) 7.45 g
  B) 14.90 g
  C) 74.50 g
  D) 149.00 g
  Show Answer
  The correct answer is D .
• Question 1523: The colour of litmus in an alkaline medium is Options:
  A) Red
  B) Yellow
  C) Pink
  D) Blue
  Show Answer
  The correct answer is D .
• Question 1524: On recrystallization, 20g of magnesium tetraoxosuphate (IV) forms 41 g of magnesium tetraoxosulphate (IV) crystals, MgSO₄. yH₂O. The value of y is?(Mg = 24, S = 32, O = 16, H = 1) Options:
  A) 1
  B) 3
  C) 5
  D) 7
  Show Answer
  The correct answer is D .
• Question 1525: The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is – (Ag = 108 F = 96500(mol^-1) Options:
  A) 54.0g
  B) 27.0g
  C) 13.5g
  D) 108.0g
  Show Answer
  The correct answer is A .
• Question 1526: X_(g) + 3Y_(g) ---- 2z_(g) H = +ve. if the reaction above takes place at room temperature, the G will be Options:
  A) negative
  B) zero
  C) positive
  D) indeterminate
  Show Answer
  The correct answer is D .
• Question 1527: How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?(Ni = 58.7, 1F = 96 500 C mol^-) Options:
  A) 0.20
  B) 0.30
  C) 0.40
  D) 0.50
  Show Answer
  The correct answer is C .
• Question 1528:

  An element having the atomic number 17 will resemble which of the following elements having atomic number as given below?

  Options:
  A) 33
  B) 35
  C) 18
  D) 19
  Show Answer
  The correct answer is B .
• Question 1529:

  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 1530: Which of the following will shift to the left from dilute tetraoxosulphate (VI) acid? Options:
  A) Lead
  B) Magnesium
  C) Cpper
  D) Gold
  Show Answer
  The correct answer is B .