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Class 9 Chemistry · Chapter 6 · Test 2

Changing Equilibrium by Concentration

25 MCQs covering the effects of adding or withdrawing reactants and products on a reversible reaction at equilibrium.

MCQs

25 questions · 18 min · 25 marks

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Sample questions

The first 5 of 25. Try each one, then tap to see the answer.

  1. Question 1

    What happens to a reversible reaction when the concentration of one reacting species is changed?

    • AIts equilibrium is disturbed
    • BIt always stops permanently
    • CIt becomes irreversible
    • DNothing can happen
    Show answer

    Answer: A

    Changing the concentration of a reacting species disturbs the state of equilibrium.

  2. Question 2

    What happens when more nitrogen gas is added to the equilibrium mixture of N₂ + 3H₂ ⇌ 2NH₃?

    • AMore ammonia is formed
    • BMore nitrogen is formed
    • CAmmonia decomposes completely
    • DNo change occurs
    Show answer

    Answer: A

    Adding nitrogen increases its concentration and causes the reaction to produce more ammonia to restore equilibrium.

  3. Question 3

    When more N₂ is added to N₂ + 3H₂ ⇌ 2NH₃ the equilibrium shifts in which direction?

    • AForward direction
    • BBackward direction
    • CNeither direction
    • DIt stops completely
    Show answer

    Answer: A

    The added nitrogen is consumed by the forward reaction to form more ammonia.

  4. Question 4

    What happens immediately when the concentration of a reactant is increased at equilibrium?

    • AThe equilibrium is disturbed
    • BThe reaction stops
    • CAll products disappear
    • DThe reaction becomes irreversible
    Show answer

    Answer: A

    Increasing a reactant concentration disturbs the existing equilibrium.

  5. Question 5

    How does the system respond after additional reactant is added?

    • AIt consumes some of the added reactant
    • BIt removes all products
    • CIt stops both reactions
    • DIt always decreases the amount of products
    Show answer

    Answer: A

    The reaction proceeds toward products and consumes some of the added reactant until a new equilibrium is reached.

More tests in Equilibria

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