Why does tear gas work?

[K.I.L.E.R]

It makes no sense.
All it does is make you cry, much like onions do.

Why don't they use sleeping gas?

 

[Bouncing Zabaglione Bros.]

Wiki, How Stuff Works. The info is already there if you look for it.

Tear gas is meant to debilitate you to stop you rioting, and disperse a crowd by making everyone feel ill. Knocking everyone out and having a big pile of sleeping people does not accomplish the same thing. Also sleeping gas is a lot more dangerous as everyone needs different doses. Just look at the Russian raid on the theatre hostages a couple of years back - many of the hostages died from an overdose of sleeping gas.

 

[Guden Oden]

Uhm, Kruno, tear gas doesn't just 'make you cry like from onion', it isn't anything like that. Instead, tear gas gives this HORRIBLE itchy, stinging sensation from literally almost every pore on your body, and particulary where the skin is thin and anywhere you got mucus membranes - which includes eyes and the entire airways I might mention.

It's awful. Pray you never have to be exposed to it. Also, it's prone to causing acute allergical reactions in some people which can result in death in severe cases. Just lovely stuff, eh?

 

[bloodbob]

Benzyl chloride ( which I've had the pleasure of working with in a lab ) forms HCl when it comes into contact with water such as on the surface of your eyeball. Of course that causes some irratation and your eye protects itself by tears.

 

[Nesh]

Also it causes breathing problems when exposed.Some people could die from tear gas.

 

[Sxotty]

It is a lachyrmator, and it can really mess up your airway as was mentioned, it is like an immediate asthma attack besides the itching and burning b/c it will make your airway swell. In summary it is nasty stuff