WAEC Chemistry questions: Chemical equilibrium

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

1. Question 1· Chemical equilibrium· WAEC

   For CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g), increasing the pressure

   • Adoes not change the position of equilibrium
   • Bshifts it to the right
   • Cshifts it to the left
   • Dstops the reaction

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   Explanation and discussion

2. Question 2· Chemical equilibrium· WAEC

   For 2SO₂ + O₂ ⇌ 2SO₃ (exothermic), lowering the temperature

   • Aincreases the yield of SO₃
   • Bdecreases the yield of SO₃
   • Chas no effect
   • Dstops the reaction

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   Explanation and discussion

3. Question 3· Chemical equilibrium· WAEC

   For N₂ + 3H₂ ⇌ 2NH₃, removing ammonia as it forms

   • Astops the reaction
   • Bshifts the equilibrium to the left
   • Chas no effect
   • Dshifts the equilibrium to the right

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   Explanation and discussion

4. Question 4· Chemical equilibrium· WAEC

   In the Contact process, the catalyst used is

   • Airon
   • Bvanadium(V) oxide
   • Cplatinum only
   • Dnickel

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   Explanation and discussion

5. Question 5· Chemical equilibrium· WAEC

   Raising the temperature of an exothermic reaction at equilibrium shifts the equilibrium

   • Anowhere
   • Bto the right
   • Cto the left
   • Duntil the reaction stops

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   Explanation and discussion

6. Question 6· 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

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   Explanation and discussion

7. Question 7· 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

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8. Question 8· 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

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   Explanation and discussion

9. Question 9· 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

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10. Question 10· Chemical equilibrium· WAEC

    Dynamic equilibrium means

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

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    Explanation and discussion

11. Question 11· 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

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    Explanation and discussion

12. Question 12· Chemical equilibrium· WAEC

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

    • Areversible
    • Birreversible
    • Cexothermic only
    • Da combustion

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    Explanation and discussion

13. Question 13· 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

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    Explanation and discussion

14. Question 14· 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

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15. Question 15· 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

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    Explanation and discussion

16. Question 16· 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

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    Explanation and discussion