Why when chopping onions dop your eyes start to water or cry.?

Answer 1

Inside the onion cells there are some chemical compounds which contain sulfur. When you cut an onion its cells are broken and those chemical compounds then undergo a reaction that transforms them into a more volatile sulfured products, which are released into the air.

These sulfured compounds react with the moisture in your eyes forming sulfuric acid, which produces a burning sensation. The nerve endings in your eyes are very sensitive and so they pick up on this irritation. The brain reacts by telling your tear ducts to produce more water, to dilute the irritating acid. So you cry to keep your eyes protected from the acid.

Answer 2

Only if the onions are really old. Fresh onions don't do that.

Edited since I got thumbs down. This is the truth. The older the onion, the worse the smell. I never have a problem with them making my eyes water because I use what I need then throw the onion away. I use a fresh onion every time. The one time I had an onion make my eyes water was at my mother's house and it was in a tupperware bowl for about a week.

Answer 3

Chopping releases the natural oils in the onion and the 'vapor' burns your eyes. Next time, try chewing a piece of gum when your chopping an onion, your eyes won't water!

Answer 4

As onions are sliced, cells are broken open. Onion cells have two sections, one with enzymes called alliinases, the other with sulfides (amino acid sulphoxides). The enzymes break down the sulphides and generate sulphenic acids. Sulphenic acids are unstable and decompose into a volatile gas called syn-propanethial-S-oxide. The gas then dissipates through the air and eventually reaches one's eye, where it will react with the water to form a dilute solution of sulphuric acid. The sulphuric acid irritates the nerve endings in the eyes, making them sting. The tear glands then produce tears to dilute and flush out the irritant.

Answer 5

When you cut into an onion, you slice through cells which contain
sulfur compounds. Sulfur is quite a noxious (bad smelling)
element. The compounds released are highly volatile, meaning they
quickly enter the air in their vicinity. Your eyes produce tears
because your body wants to wash or dilute the chemicals before they
effect your eyes. The tears are a natural way the body can wash
the offensive chemicals away.


See the link below:

Answer 6

Onions contain cells with a particular enzyme that when the cells are broken, this enzyme escapes. When this happens, some of the enzymes decompose into amino acid sulfoxides that when introduced into the air, form the gas sulfuric acid (this is what makes you cry).Store your onions in the fridge,so that you won't cry everytime you chop onions.

Answer 7

This is a natural response due to the onion's release of the chemical irritant known as syn-propanethial-S-oxide. It stimulates the eyes' lachrymal glands so they release tears.

Try peeling the onion and chilling it before slicing to lessen this effect.

Answer 8

Chopping Onions produces some juice that winds up in the eyes, and the eyes react to the onion juice arriving or slattering in the eye.

Answer 9

Chop the root off the botton, cut in half from top to baseless bottom, peel away the layers inedible skin from each half, slice from botton to just below the top, cut across the sliced portion and bin the top. By leaving the top on until last it should stop you being affected by the smell. That's the theory I use anyway and it works for me. Wash your hands afterwards.

Answer 10

Beacause you expose vapors that are released by cutting into the skin of the onion.

These vapors are slightly acidic, and when they reach your eyes, your eyes will water to dispel the fumes and prevent them from causing damage.