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Chemistry Chapter 9 : Topic 2
Equilibrium Condition Changes
1 / 22
When copper (II) sulfate pentahydrate is heated, it loses its water of crystallization. What is the correct interpretation of this change?
Reasoning: Heating removes water of crystallization reversibly, forming anhydrous CuSO₄, which can regain water.
2 / 22
What happens when water is added to anhydrous copper (II) sulfate?
Reasoning: Anhydrous CuSO₄ is white and turns blue when hydrated, forming CuSO₄·5H₂O.
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Which statement best explains reversible hydration in cobalt (II) chloride?
Reasoning: CoCl₂ changes color (blue ↔ pink) depending on hydration, showing reversibility.
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Anhydrous cobalt (II) chloride is usually:
Reasoning: Anhydrous CoCl₂ is blue, while hydrated form is pink.
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What causes the color change in cobalt (II) chloride when exposed to moisture?
Reasoning: Water molecules alter crystal field, changing color reversibly.
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Heating hydrated copper (II) sulfate shifts equilibrium in which direction?
Reasoning: Heat removes water, shifting equilibrium toward anhydrous CuSO₄.
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Which of the following best represents a reversible equilibrium in hydrated salts?
Reasoning: Hydration and dehydration form a reversible equilibrium.
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If a blue sample of copper (II) sulfate is heated strongly, it turns:
Reasoning: Water is removed, forming white anhydrous CuSO₄.
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What is the role of water in the hydration of cobalt (II) chloride?
Reasoning: Water molecules coordinate with CoCl₂ forming hydrated salt.
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Which condition will convert blue cobalt (II) chloride paper into pink?
Reasoning: Moisture provides water molecules for hydration.
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Which observation confirms that hydration reactions are reversible?
Reasoning: Reversible color changes show equilibrium behavior.
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Why is copper (II) sulfate used in laboratories to detect water?
Reasoning: Hydration causes a visible color change.
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Which statement best describes anhydrous substances?
Reasoning: Anhydrous means without water molecules in structure.
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What happens when hydrated cobalt (II) chloride is heated?
Reasoning: Heating removes water, producing blue anhydrous CoCl₂.
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Which of the following processes is most affected by humidity?
Reasoning: Moisture directly affects hydration equilibrium.
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The reversible change between CuSO₄ and CuSO₄·5H₂O is an example of:
Reasoning: It involves physical gain / loss of water.
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Why does anhydrous copper (II) sulfate turn blue when water is added?
Reasoning: Water molecules form hydrated CuSO₄·5H₂O.
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Which factor shifts hydration equilibrium toward anhydrous form?
Reasoning: Heat removes water from hydrated salts.
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A student observes that cobalt chloride paper turns pink in a humid room. This indicates:
Reasoning: Pink color shows hydrated form due to moisture.
20 / 22
Which best describes the nature of hydration-dehydration equilibrium?
Reasoning: Water molecules continuously attach and detach in equilibrium.
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What is the effect of removing moisture from cobalt chloride equilibrium?
Reasoning: Removing water favors anhydrous blue CoCl₂.
22 / 22
Which observation shows that a reaction system is in equilibrium between hydrated and anhydrous states?
Reasoning: Reversible visible changes indicate dynamic equilibrium.
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