Andy Brewer, age 17, of Grand Forks, N.D., for his question:

HOW IS ANILINE USED?

Aniline is a chemical best known for its use in making dyes. Aniline is used by industries in dyes to color textiles and in making inks, paints and varnishes.

Aniline became important in 1856 when an English chemist named William Perkins accidentally made a violet dye from aniline.

Bacteriologists use the dyes to stain bacteria and other organisms. Industries also use aniline in making drugs, explosives, rocket fuels and other products.

In the lab, chemists prepare aniline by first reducing nitrobenzene with iron filings and hydrochloric acid. In industry, aniline is prepared by heating chlorobenzene and ammonia under high pressure, or by catalytic reduction of nitrobenzene.

Aniline is a colorless, oily liquid that is only slightly soluble in water. It has a strong, pleasing odor, but is highly poisonous.