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 41: In an electrochemical cell, polarization is caused by Options:
  A) Oxygen
  B) Hydrogen
  C) Tetraoxosulphate(IV) acid
  D) Chlorine
  Show Answer
  The correct answer is B .
• Question 42: How many hydrogen atoms does a single ring cycloalkane have less than the corresponding open-chain alkane? Options:
  A) Two
  B) Three
  C) Four
  D) One
  Show Answer
  The correct answer is A .
• Question 43: Which of the following represent hybridization in ethyne? Options:
  A) Sp²
  B) Sp²d
  C) Sp³
  D) Sp
  Show Answer
  The correct answer is D .
• Question 44:

  The type of bonding in [Cu(NH${}_3$)${}^4$]${}^{2+}$ is 

  Options:
  A) coordinate
  B) electrovalent
  C) metallic
  D) covalent
  Show Answer
  The correct answer is A .
• Question 45: An isotope has an atomic number of 15 and a mass number of 31. The number of proton it contains is Options:
  A) 16
  B) 15
  C) 31
  D) 46
  Show Answer
  The correct answer is B .
• Question 46: An example of an acidic oxide is Options:
  A) NO
  B) CO
  C) SO₂
  D) CuO
  Show Answer
  The correct answer is C .
• Question 47:

  Which transition metal is known for its multiple colorful oxidation states and compounds used in pigments and paints?

  Options:
  A) Silver (Ag)
  B) Copper (Cu)
  C) Gold (Au)
  D) Zinc (Zn)
  Show Answer
  The correct answer is B .
• Question 48:

  

  In the diagram above, which of the curves represents the evolution of oxygen with time in the equation 2KClO_3(s) → 2KCl_(s) + 3O_2(g)?

  Options:
  A) X
  B) Y
  C) Z
  D) R
  Show Answer
  The correct answer is C .
• Question 49:

  Which of the following gases contains the least number of atoms at s.t.p?

  Options:
  A) 1 mole of butane
  B) 4 moles of chlorine
  C) 3 moles of ozone
  D) 7 moles of argon
  Show Answer
  The correct answer is A .
• Question 50: There is a large temperature interval between the melting point and the boiling point of a metal because? Options:
  A) metals have very high melting points
  B) metals conduct heat very rapidly
  C) melting does not break the metallic bond but boiling does
  D) the crystal lattice of metals is easily broken
  Show Answer
  The correct answer is C .