Sulfuric acid drain cleaners are a "heavy-duty" option that should be treated with respect. They are best reserved for professional use or as a last resort when mechanical methods like snaking have failed. For the average user, the potential for personal injury and pipe damage often outweighs the convenience of a quick fix.
The acid's high affinity for water allows it to pull hydrogen and oxygen out of substances, effectively "charring" organic matter into carbon. When to Use (and When to Avoid) sulphuric acid drain cleaner