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MDCAT
Chemistry
2024

Chemistry · States of Matter - Gases, Liquids and Solids

Work through this past-paper style MCQ, then read the full explanation. Practice more chemistry questions on mMCQ with adaptive practice and topic analytics.

Question

Ag₂SO₄ and Na₂SO₄ are the:

Options
  • A

    Polymorphs

  • B

    Isomorphs

  • C

    Allomorphs

  • D

    Anisotropes

Explanation

Ag₂SO₄ (Silver sulfate) and Na₂SO₄ (Sodium sulfate) are isomorphs.

Here's why:

  • Isomorphs: Isomorphs are substances that have different chemical compositions but crystallize in the same crystal structure. This is possible when the constituent ions have similar sizes and charges, allowing them to fit into the same lattice structure.

Ag₂SO₄ and Na₂SO₄ have similar structures in their anhydrous forms. They both contain a sulfate anion (SO₄²⁻) and two singly charged cations (Ag⁺ or Na⁺). The sizes and charges of Ag⁺ and Na⁺ are close enough to allow for the formation of similar crystal lattices.

Here's why the other options are incorrect:

  • Polymorphs: Polymorphs are substances that have the same chemical composition but crystallize in different crystal structures (e.g., diamond and graphite are polymorphs of carbon). 
  • Allomorphs: This term is less common now and is often used synonymously with polymorphs, referring to different structural forms of an element.
  • Anisotropes: Anisotropy refers to the property of a substance having different physical properties when measured in different directions. This is a general property of many crystalline solids but doesn't define the relationship between Ag₂SO₄ and Na₂SO₄. 

Therefore, the relationship between Ag₂SO₄ and Na₂SO₄ is best described as isomorphism.

This is not correct

Ag₂SO₄ (Silver sulfate) and Na₂SO₄ (Sodium sulfate) are isomorphs.

Here's why:

  • Isomorphs: Isomorphs are substances that have different chemical compositions but crystallize in the same crystal structure. This is possible when the constituent ions have similar sizes and charges, allowing them to fit into the same lattice structure.

Ag₂SO₄ and Na₂SO₄ have similar structures in their anhydrous forms. They both contain a sulfate anion (SO₄²⁻) and two singly charged cations (Ag⁺ or Na⁺). The sizes and charges of Ag⁺ and Na⁺ are close enough to allow for the formation of similar crystal lattices.

Here's why the other options are incorrect:

  • Polymorphs: Polymorphs are substances that have the same chemical composition but crystallize in different crystal structures (e.g., diamond and graphite are polymorphs of carbon). 
  • Allomorphs: This term is less common now and is often used synonymously with polymorphs, referring to different structural forms of an element.
  • Anisotropes: Anisotropy refers to the property of a substance having different physical properties when measured in different directions. This is a general property of many crystalline solids but doesn't define the relationship between Ag₂SO₄ and Na₂SO₄. 

Therefore, the relationship between Ag₂SO₄ and Na₂SO₄ is best described as isomorphism.

This is not correct

This is not correct

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Tagged under Chemistry · States of Matter - Gases, Liquids and Solids · 2024