WHY DO EYES PRODUCE TEARS WHEN TEAR GAS IS USED?

ANSWER :-

Tear gas, in the form of CN (chlorocetophenone) or CS (chlorobenzylidemalononitrile) is often used for law enforcement. Today, CS has largely replaced CN and is probably the most widely used tear gas internationally. The tear gas is either launched in the form of grenades or aerosol cans so that the liquid becomes an aerosol.

Both CN and CS are skin irritants — they irritate mucous membranes in the eyes, nose, mouth and lungs, and cause tearing, sneezing, coughing. The more moisture on our body, the faster the acid is created and tissues are damaged, causing pain. When it is contacted with moist eyes, it affects mucous membranes which initiates glands to shed more tears.