Why eyes cry when chopping onions?

Why eyes cry when chopping onions? - Almost everyone knows that peeling and slicing onions or onion can make the tears flow. But what is the cause?When onions are sliced, cells in it were damaged. Exit the named compound that reacts with the sulfenic acid enzyme and produce a gas called Propanethiol S-oxide. If the gas enters the eye and is mixed with water in it, it forms sulfuric acid.Presence