WAEC Chemistry questions

357 questions with answers and explanations. Tap an option to check yourself.

1. Question 101· Chemical equilibrium· WAEC

   For the reaction N₂ + 3H₂ ⇌ 2NH₃, increasing the pressure

   • Ashifts the equilibrium to the right
   • Bshifts the equilibrium to the left
   • Chas no effect
   • Dstops the reaction

   Show answer

   Explanation and discussion

2. Question 102· Chemical equilibrium· WAEC

   For H₂(g) + I₂(g) ⇌ 2HI(g), changing the pressure

   • Adoes not alter the position of equilibrium
   • Bshifts it to the right
   • Cshifts it to the left
   • Ddoubles the amount of HI

   Show answer

   Explanation and discussion

3. Question 103· Chemical equilibrium· WAEC

   For the exothermic reaction N₂(g) + 3H₂(g) ⇌ 2NH₃(g), raising the temperature

   • Ashifts the equilibrium to the left and lowers the yield of ammonia
   • Bshifts the equilibrium to the right
   • Chas no effect on the yield
   • Dincreases the yield of ammonia

   Show answer

   Explanation and discussion

4. Question 104· Chemical equilibrium· WAEC

   Heating blue hydrated copper(II) tetraoxosulphate(VI) turns it white; adding water turns it blue again. This shows that the change is

   • Aa combustion
   • Birreversible
   • Ca physical change only
   • Dreversible

   Show answer

   Explanation and discussion

5. Question 105· Chemical equilibrium· WAEC

   Dynamic equilibrium means

   • Aonly reactants remain
   • Bthe reaction has stopped
   • Conly products remain
   • Dforward and backward reactions continue at equal rates

   Show answer

   Explanation and discussion

6. Question 106· Chemical equilibrium· WAEC

   Le Chatelier's principle states that when a system at equilibrium is disturbed, it

   • Agoes to completion
   • Bstops reacting
   • Cshifts so as to oppose the change
   • Dreleases all its energy

   Show answer

   Explanation and discussion

7. Question 107· Chemical equilibrium· WAEC

   A reaction that can proceed in both the forward and backward directions is

   • Areversible
   • Birreversible
   • Cexothermic only
   • Da combustion

   Show answer

   Explanation and discussion

8. Question 108· Chemical equilibrium· WAEC

   A catalyst added to a system at equilibrium

   • Ashifts the equilibrium to the right
   • Bspeeds up both forward and backward reactions equally
   • Cincreases yield
   • Dstops the reaction

   Show answer

   Explanation and discussion

9. Question 109· Chemical equilibrium· WAEC

   For N₂ + 3H₂ ⇌ 2NH₃ (ΔH negative), the yield of ammonia increases if

   • Atemperature is increased
   • Bpressure is increased
   • Cammonia is added
   • Da catalyst is removed

   Show answer

   Explanation and discussion

10. Question 110· Chemical equilibrium· WAEC

    Adding a catalyst to a system at equilibrium

    • Amakes equilibrium reached faster without changing its position
    • Bincreases the yield of products
    • Cshifts the equilibrium to the right
    • Dshifts the equilibrium to the left

    Show answer

    Explanation and discussion

11. Question 111· Chemical equilibrium· WAEC

    For N₂(g) + 3H₂(g) ⇌ 2NH₃(g), increasing the pressure

    • Ahas no effect on the equilibrium
    • Bshifts the equilibrium to the left
    • Cshifts the equilibrium to the right
    • Dstops the reaction

    Show answer

    Explanation and discussion

12. Question 112· Chemistry and industry· WAEC

    Nitrogen-containing fertilisers such as urea are produced in Nigeria using ammonia made by

    • Athe contact process
    • Bthe Haber process
    • Cthe Solvay process
    • Dfermentation

    Show answer

    Explanation and discussion

13. Question 113· Chemistry and industry· WAEC

    The Haber process is used to manufacture

    • Aammonia
    • Bsulphuric acid
    • Cnitric acid
    • Dchlorine

    Show answer

    Explanation and discussion

14. Question 114· Chemistry and industry· WAEC

    Fertiliser plants in Nigeria use natural gas mainly as a source of

    • Ahydrogen for ammonia production
    • Boxygen
    • Cnitrogen only
    • Dchlorine

    Show answer

    Explanation and discussion

15. Question 115· Chemistry and industry· WAEC

    Soap is made by boiling fats or oils with

    • Aethanol
    • Bsulphuric acid
    • Csodium hydroxide
    • Dsodium chloride

    Show answer

    Explanation and discussion

16. Question 116· Chemistry and industry· WAEC

    The fraction of crude oil used as fuel for jet aircraft is

    • Abitumen
    • Bkerosene
    • Clubricating oil
    • Dpetroleum gas

    Show answer

    Explanation and discussion

17. Question 117· Chemistry and industry· WAEC

    Margarine is made by hydrogenating vegetable oils over a catalyst of

    • Airon
    • Bnickel
    • Cplatinum
    • Dcopper

    Show answer

    Explanation and discussion

18. Question 118· Chemistry and industry· WAEC

    The main raw material for making glass is

    • Asand
    • Bclay
    • Climestone only
    • Diron ore

    Show answer

    Explanation and discussion

19. Question 119· Chemistry and industry· WAEC

    The catalyst used in the contact process for making sulphuric acid is

    • Airon
    • Bnickel
    • Cplatinum
    • Dvanadium(V) oxide

    Show answer

    Explanation and discussion

20. Question 120· Chemistry and industry· WAEC

    Crude oil is separated into fractions such as petrol and kerosene by

    • Afractional distillation
    • Bfiltration
    • Ccracking only
    • Delectrolysis

    Show answer

    Explanation and discussion