Why is thionyl chloride often preferred over PCl₅ for converting a carboxylic acid into an acyl chloride?

1. A Option A: It does not need dry conditions
2. B Option B: It gives an ester directly
3. C Option C: The by-products SO₂ and HCl are gases and escape easily
4. D Option D: It produces phosphoric acid as a useful by-product

Answer checked 11 October 2026 · How we write and check questions