Hydrogen chloride (HCl) is an important by-product of the chemical industry—and can be electrolyzed to generate hydrogen and chlorine. Chlorine is one of the most important base chemicals ...

The mass of hydrogen is the lowest of all the atoms. These low masses help explain why polyethylene has a low density. Another reason is that these long skinny molecules are loosely packed together.

A cotton swab is dipped into concentrated hydrochloric acid (producing hydrogen chloride gas) while a second on is dipped into concentrated aqueous ammonia (producing ammonia gas). Both cotton swabs ...