The Infrared Absorption of Solutions of Hydroxides and Hydrolyzing Salts

Absorption bands have been found at 3.65μ and 5.2μ in aqueous solutions of NaOH, KOH and LiOH. Solutions of ZnCl2, ZnBr2, NH4C2H3O2, Na2CO3, NaC2H3O2, Na2B4O7, Na2SiO3 and Al2(SO4)3 were studied in the region from 2.8μ to 6μ and bands were observed at about 3.45μ, 4.5μ, 5.2μ and 5.6μ. The solutions which are acid in reaction had intense bands at 3.6μ and 5.2μ, while the basic solutions gave a strong band at 5.6μ. This variation in intensity indicates that the absorption bands are due to undissociated molecules bound to water molecules. The band at 4.5μ is probably due to water which has been modified by the ions. The hydroxides showed the absorption bands at 3.6μ and 5.2μ when 0.1N solution was used.