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 2191: If excess zinc is added to a bluish green solution of copper (II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because Options:
  A) both zinc and copper are metals
  B) the sulphate radical and the zinc ion are divalent
  C) zinc is more electropositive than copper
  D) both zinc and copper form depositive ions in solution
  E) zinc is a reducing agent
  Show Answer
  The correct answer is C .
• Question 2192:

  

  Which of the structural forms above is ethanoic acid is

  Options:
  A) A
  B) B
  C) C
  D) D
  E) E
  Show Answer
  The correct answer is E .
• Question 2193: Which of the following gases will rekindle a brightly glowing splint? Options:
  A) NO₂
  B) NO
  C) N₂O
  D) CI₂
  Show Answer
  The correct answer is C .
• Question 2194: the elements that belong to the third period of the periodic table are Options:
  A) Li, Be, Al and P
  B) Na, P, O and Cl
  C) B, C, N and O
  D) Nz, Mg, S and Ar
  Show Answer
  The correct answer is D .
• Question 2195: Which of the following methods may be used to prepare trioxonitrate (V) acid (nitric acid) in the laboratory? Options:
  A) Heating ammonia gas with tetraoxosulphate (VI) acid
  B) Heating ammonium trioxonitrate (V) with tetraoxosulphate (VI) acid
  C) Heating sodium trioxonitrate (V) with tetraoxosulphate (VI) acid
  D) Heating potassium trioxonitrate (V) with calcium hydroxide
  E) Heating a mixture of ammonia gas and oxygen.
  Show Answer
  The correct answer is C .
• Question 2196:

  6AgNO_4(aq) + PH_3(g) + 3H₂O_(l) → 6Ag_(s) + H₃PO_3(g) + 6HNO_3(aq)

  In the above reaction, the reducing agent is

  Options:
  A) HNO_3(aq)
  B) H₂O_(l)
  C) PH_3(g)
  D) AgNO_3(aq)
  Show Answer
  The correct answer is C .
• Question 2197: How many grams of HBr would exactly be required to react with 2 g of propyne? (C =12, H=1, Br = 80) Options:
  A) 4. 1 g
  B) 6. 1 g
  C) 8. 1g
  D) 16.2g
  Show Answer
  The correct answer is C .
• Question 2198: Atomicity of ozone is Options:
  A) 1
  B) 2
  C) 3
  D) 4
  Show Answer
  The correct answer is C .
• Question 2199: Soap lather is an example of a colloid in which a? Options:
  A) liquid is dispersed in gas
  B) solid is dispersed in liquid
  C) gas is dispersed in liquid
  D) liquid is despersed in liquid
  Show Answer
  The correct answer is C .
• Question 2200:

  For the general equation of the nature

  XP + yQ ⇌ mR + nS, the expression for the equilibrium constant is

  Options:
  A) k[P]${}^x$[Q]${}^y$
  B) $\frac{m[R][S]}{x[P]y[Q]}$
  C) $\frac{[P{]}^x[Q{]}^y}{[R{]}^m[S{]}^n}$
  D) $\frac{[R{]}^m[S{]}^n}{[P{]}^x[Q{]}^y}$
  Show Answer
  The correct answer is D .