Aspirin--Acetyl Salicyclic Acid
"Aspirin, an acetyl derivative of salicylic acid, is a white, crystalline, weakly acidic substance, with a melting 
point of 135 °C (275 °F). Acetylsalicylic acid decomposes rapidly in solutions of ammonium acetate or of the acetates, carbonates, citrates or hydroxides of the alkali metals. Acetylsalicylic acid is stable in dry air, but gradually hydrolyses in contact with moisture to acetic and salicylic acids. In solution with alkalis, the hydrolysis proceeds rapidly and the clear solutions formed may consist entirely of acetate and salicylate."