This document discusses acetylene and acetaldehyde. It provides their chemical formulas, IUPAC names, molar masses, melting points, boiling points, densities, and other properties. It then describes some of their applications, which include use in paints, plastics, pharmaceuticals, foods, and more. The document also outlines the Chisso process for producing acetaldehyde, noting that it involves hydrating acetylene with water and a catalyst in a reactor, then distilling and condensing the resulting acetaldehyde.