Substance, ordinarily a liquid, in which other materials dissolve to form a solution. Polar solvents (e.g., water) favour formation of ions; nonpolar ones (e.g., hydrocarbons) do not. Solvents may be predominantly acidic, predominantly basic, amphoteric (both), or aprotic (neither). Organic compounds used as solvents include aromatic compounds and other hydrocarbons, alcohols, esters, ethers, ketones, amines, and nitrated and halogenated hydrocarbons. Their chief uses are as media for chemical syntheses, as industrial cleaners, in extractive processes, in pharmaceuticals, in inks, and in paints, varnishes, and lacquers.