what is the basic reaction when chloroform evaporates to get fainting?

Answer 1

There is no chemical reaction -- just the vaporization of liquid chloroform. The reason the individual faints is not from the chloroform, but from the absence of air (specifically oxygen).

Since chloroform is a very dense gas a compared to oxygen, it can displace the surrounding air and render a person unconscious. But, again, this comes not so much from the PRESENCE of chloroform, as from the ABSENCE of oxygen (pushed aside by the denser chloroform vapor).

Answer 2

FrankM is correct. Chloroform also has anesthetic (pain relieving) effect.

Chloroform does not make you pass out like in the movies when they spray someone with a can of it or put it on a rag and hold it over someones nose. Headache and dizziness are common side effect of exposure, liver damage being one of the worst.

Answer 3

I think that the chloroform turns to a mist/gas when inhaled, causes an individual to faint/ fall asleep. I think it is osmosis

Answer 4

I breathe choloroform everyday; the movies play it up a lot, but it really takes a long time exposure, and a significant amount to actually cause someone to faint. Holding a rag soaked with it is just gonna piss them off more than "render them unconscious".