(inorganic chemistry) The compound arsine, H₃As or AsH₃.

(chemistry) chlorous acid

(chemistry) acetic acid

(inorganic chemistry) A toxic gas, H₂S, smelling like rotten eggs and used in analytical chemistry and industry.

(obsolete, chemistry) hydrogen

(chemistry) Used other than figuratively or idiomatically: see hydrogen, ion. ; H⁻ or H⁺

(chemistry, physics) an electrode in which hydrogen gas is adsorbed on platinum

(informal) dihydrogen monoxide (water (H₂O), but not hydrogen peroxide (H₂O₂) or the hydroxyl radical (-OH))

(inorganic chemistry) An inorganic compound with the formula HCl. Forms hydrochloric acid when dissolved in water.

(chemistry) chloric acid