Boric acid is solid, whereas BF3 is gas at room temperature because of
p-Block Elements (Class 11) · Class 11 · JEE Main Previous Year Question
Boric acid is solid, whereas is gas at room temperature because of
- a
Strong ionic bond in Boric acid
- b
Strong van der Waals' interaction in Boric acid
- c✓
Strong hydrogen bond in Boric acid
- d
Strong covalent bond in
Strong hydrogen bond in Boric acid
Strategy: Explain why boric acid is a solid while BF₃ is a gas, by comparing intermolecular forces.
Step 1: Structure of Boric Acid has a layered structure. Each unit is planar, and the layers are held together by an extensive two-dimensional hydrogen bond network (O–H···O). These hydrogen bonds are strong, requiring significant energy to break, making a solid at room temperature (mp ≈ 170 °C).
Step 2: Structure of BF₃ is a covalent, trigonal planar molecule with no hydrogen bond donors/acceptors. The only intermolecular forces are weak van der Waals forces, making it a gas at room temperature (bp ≈ −100 °C).
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