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 111: 25cm³ of a mixture of nobel gases was obtained from air after the removal of other constituents. What was the original volume of air Options:
  A) 2,500 cm³
  B) 1250 cm³
  C) 125 cm³
  D) 80 cm³
  Show Answer
  The correct answer is A .
• Question 112: When water boilers are used for long period of time, the solid substances left behind as scale are Options:
  A) magnesium trioxosilicate (IV) and rust
  B) magnesium trioxosilicate (IV) and calcium tetraoxosulphate (VI)
  C) clay and magnesium troxosulphate (IV)
  D) clay and rust
  Show Answer
  The correct answer is A .
• Question 113:

  

  At what temperature is the solubility of potassium trioxonitrate(V ) equal to that of sodium trioxonitrate (V)?

  Options:
  A) 0${}^o$c
  B) 30${}^o$c
  C) 40${}^o$c
  D) 45${}^o$c
  Show Answer
  The correct answer is D .
• Question 114: The conversion of open chain alkanes into cycloalkanes and aromatic compounds is called Options:
  A) cracking
  B) reforming
  C) isomerization
  D) polymerization
  Show Answer
  The correct answer is B .
• Question 115:

  The reactivity of fluorine is due to?

  Options:
  A) its high electro negativity
  B) small size of fluorine atom
  C) availability of D-orbitals
  D) strong f-f bond
  Show Answer
  The correct answer is A .
• Question 116: Carbon is tetravalent because Options:
  A) The electrons in both the 2s and 2p orbitals are equivalent
  B) The electrons in all the orbitals of carbon are equivalent
  C) The 2s and 2p atomic orbitals hybridize
  D) All the atomic orbitals of carbon hybridize
  Show Answer
  The correct answer is A .
• Question 117:

  The nucleusof a hydrogen atom consist of a?

  Options:
  A) 1 proton only
  B) 1 proton, 2 neutron
  C) 1 neutron only
  D) 1 electron only
  Show Answer
  The correct answer is A .
• Question 118:

  Which halogen is a gas at room temperature and is pale yellow in color?

  Options:
  A) Chlorine (Cl)
  B) Fluorine (F)
  C) Iodine (I)
  D) Bromine (Br)
  Show Answer
  The correct answer is B .
• Question 119:

  3Cu_(s) + 8HNO_3(aq) 3Cu(NO₃)_2(aq) + 4H₂O_(l) + 2NO_(g)

  In the equation above, copper is

  Options:
  A) an electron acceptor
  B) a base
  C) an oxidizing agent
  D) a reducing agent
  Show Answer
  The correct answer is D .
• Question 120: Which of the following statement is true of the electrochemical series? Options:
  A) Electropositivity of metals increase down the series
  B) Electropositivity of non-metals decrease down the series
  C) Electronegativity of non-metals decrease down the series
  D) Electropositivity of metals decreases down the series
  Show Answer
  The correct answer is D .