Why is fluorine the strongest oxidising agent among halogens?

F has the highest electronegativity, smallest size, and weakest F-F bond. This makes it easiest to gain an electron, giving it the highest oxidising power. It can oxidise even water.

Why is HF a weak acid despite fluorine being the most electronegative?

The H-F bond has such high bond energy (570 kJ/mol) that HF dissociates poorly in water. Strong electronegativity causes strong bonding, not weak bonding.

What is the Contact Process?

Industrial production of H₂SO₄: S is burned to SO₂, then SO₂ is oxidised to SO₃ using V₂O₅ catalyst at 450°C and 2 atm. SO₃ is absorbed in H₂SO₄ to give oleum, then diluted.

Group 15, 16, and 17 Elements

p-Block Elements • Class 11 Chemistry • NCERT • CBSE

Group 15 (N, P, As): +3/+5 oxidation states, forms oxides and hydrides. Group 16 (O, S, Se): −2 to +6 states, H₂SO₄ concentrated is dehydrating agent. Group 17 halogens: strong oxidising agents, F most electronegative element.

Key Formulas

Haber Process: N₂ + 3H₂ → 2NH₃ (450°C, Fe, 200 atm)
Ostwald Process: 4NH₃ + 5O₂ → 4NO + 6H₂O
Contact Process: 2SO₂ + O₂ → 2SO₃ (V₂O₅, 450°C)
Ozone test: O₃ + 2KI + H₂O → 2KOH + I₂ + O₂

Frequently Asked Questions

Why is fluorine the strongest oxidising agent among halogens?: F has the highest electronegativity, smallest size, and weakest F-F bond. This makes it easiest to gain an electron, giving it the highest oxidising power. It can oxidise even water.
Why is HF a weak acid despite fluorine being the most electronegative?: The H-F bond has such high bond energy (570 kJ/mol) that HF dissociates poorly in water. Strong electronegativity causes strong bonding, not weak bonding.
What is the Contact Process?: Industrial production of H₂SO₄: S is burned to SO₂, then SO₂ is oxidised to SO₃ using V₂O₅ catalyst at 450°C and 2 atm. SO₃ is absorbed in H₂SO₄ to give oleum, then diluted.

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