12.89P - Chemistry: Molecular Nature Of Matter And Change

Question

Of the five major types of crystalline solid, which does each of the following forms, and why: (a) SiC; (b) Na₂SO₄; (c) SF₆; (d) cholesterol (C₂₇H₄₅OH) ; (e) KCl; (f) BN?

Step-by-Step Solution

Answer

(a) Covalent

(b) Ionic

(c) Molecular

(d) Molecular

(e) Ionic

(f) Covalent

Step 1: Some types of crystalline solids

Covalent solids are crystalline solids with atoms as the entities bonded by covalent bonds.

 

Ionic solids are solid with ions as constituent entities bonded by electrostatic force.

 

Molecular solids are crystalline solids with molecules bonded with van der wall forces.

Step 2: Silicon Carbide

Silicon carbide is a covalent compound similar to diamond where Si atoms are covalently bonded to C atoms. Hence, the compound structure is covalent solid.

Step 3: Sodium Sulphate

Sodium sulphate is an ionic compound in which the constituent ions ${\mathbf{Na}}^{\mathbf{+}}$ and ${{\mathbf{SO}}_{\mathbf{4}}}^{\mathbf{2}\mathbf{-}}$ are bonded with ionic bonding. Hence, the compound structure is ionic solid.

Step 4: Sulphur fluoride

Sulphur fluoride is a molecule and thus the structure is a molecular crystalline solid.

Step 5: Cholesterol

Cholesterol is a molecule with carbon, hydrogen and oxygen as constituent atoms and thus the structure is a molecular crystalline solid.

Step 6: Potassium Chloride

Potassium chloride is an ionic compound with ${\mathbf{K}}^{\mathbf{+}}$ and ${\mathbf{Cl}}^{\mathbf{-}}$ as the constituent ions, thus the structure being a crystalline ionic solid.

Step 7: Boron Nitride

Boron Nitride is a covalent compound with the structure being a crystalline covalent solid.