what are two things halogens are used for?

Answer 1

Chlorine makes a great cleanser.
Iodine is a necessary ingredient for human life so it is added to our table salt.

The reactivity of halogens make for some pretty strong acids like hydrochloric acid and hydrofluoric acid.

Carbon Fluorides were once used as propellants for spray cans and for cooling agents like freon. The destruction done to the ozone layer caused a change in the laws to prevent the use of these gases.

Halogens are great oxidizing agents, they are important ingredients in dangerous weapons like Mustard Gas (bis(2-chloroethyl) sulfide: http://en.wikipedia.org/wiki/Mustard_Gas).
As a rule Halogens are poisonous and dangerous to use.

According to Wikipedia: http://en.wikipedia.org/wiki/Halogens
"The halogens or halogen elements are a series of nonmetal elements from Group 17 (old-style: VII or VIIA; Group 7 IUPAC Style) of the periodic table, comprising fluorine, F; chlorine, Cl; bromine, Br; iodine, I; and astatine, At. The undiscovered element 117, temporarily named ununseptium, may also be considered a halogen.

The group of halogens is the only group which contains elements in all three familiar states of matter at standard temperature and pressure."

Answer 2

Halogens, has a lot of uses. either by themselves of as compound.

Halogen, is used in certain Fire Fighting situation, where water cannot be used, Carbon dioxide does not meet the reaction time. Halogen system rapidly bind with the Oxygen in the area, killing the fire.

Halogen, used as compound, Chlorine (as in Sodium Chloride, or other form of Chlorides).

Halogen in Health, Iodine, need for the proper function of body function.

Fluorine and Chlorine is added domestic water supply, the usage is has some controversies behind it, but generally practised by most industrial countries.

Read the Source for more information.

Answer 3

lighting and air conditioning