What is the difference between your ammonium sulfite and ammonium bisulfite?

Ammonium sulfite ((NH₄)₂SO₃) is typically available as crystals and used in paper, water treatment, and environmental applications. Ammonium bisulfite (NH₄HSO₃) is a liquid solution with higher reducibility, ideal for pharmaceuticals, petroleum drilling, and food processing. Both are efficient reductants but differ in form and specific uses.