Sodium dihydrogen arsenate pyroarsenate salt NaHAsO. Sodium dihydrogen arsenate Sodium dihydrogen arsenate is the inorganic compound with the formula NaHAsO. Related salts are also called sodium arsenate, including NaHAsO (disodium hydrogen arsenate) and NaHAsO (sodium dihydrogen arsenate). Sodium dihydrogen arsenate is a colorless solid that is highly toxic. The salt is the conjugate base of arsenic acid: In the laboratory, it is prepared in this way, crystallizing from a hot saturated aqueous solution, where it is highly soluble when hot (75.3 g in 100 mL at 100 °C). It is obtained as the monohydrate. Upon heating, solid NaHAsOHO, loses water of crystallization and
Ethylene oxide oxide with compounds containing active methylene group leads to the formation of butyrolactones: Ethylene oxide enters into the Friedel–Crafts reaction with benzene to form phenethyl alcohol: Styrene can be obtained in one stage if this reaction is conducted at elevated temperatures () and pressures (), in presence of an aluminosilicate catalyst. A series of polynomial heterocyclic compounds, known as crown ethers, can be synthesized with ethylene oxide. One method is the cationic cyclopolymerization of ethylene oxide, limiting the size of the formed cycle: To suppress the formation of other linear polymers the reaction is carried out in a highly dilute