Propargyl chloride, CH≡C–CH2Cl, was virtually inert towards NaH2AsO3, reacted to a very small extent with Na2HAsO3, but with Na3AsO3 gave a mixture of salts in which sodium 1-propynylarsonate, CH3–C≡C–AsO3Na2 6, predominated, the allenylarsonate, CH2 = C = CH–AsO3Na2 4, being present in (very) small amounts, while the isomeric 2-propynylarsonate CH≡C–CH2–AsO3Na2 5 was not detected. These results can be understood by attack of AsO33– on propargyl chloride to form 5 followed by base catalyzed prototropic rearrangements to 4 and to 6. Separation of 6 from 4 was tried as acids or salts without success. The purity of the product as acid 6 and lead salt of 6 was >80%. The reaction of propargyl chloride with Na2SO3 required dilute aqueous solutions (∼0.3 M) in order to give the salt CH≡C–CH2–SO3Na·4H2O, 11·4H2O, in ∼80% yields. More concentrated solutions (1 or 2 M) produced 11 and by-products from which CH2 = C = CH-SO3Na 10, but not CH3–C≡C–SO3Na 12, has been identified spectroscopically, while potassium 2-chloro-2-propenylsulfonate tetrahydrate CH2 = CCl–CH2–SO3K·4H2O, 13·4H2O, was isolated.