Reaction of ClONO₂ with HCl on NAT, NAD, and frozen sulfuric acid and hydrolysis of N₂O₅ and ClONO₂ on frozen sulfuric acid

The reaction of ClONO 2 with HCl on the nitric acid trihydrate (NAT) and dihydrate (NAD) and on frozen sulfuric acid solutions was studied as functions of reactant concentration and temperature representative of the stratosphere. A flow tube reactor equipped with a chemical ionization mass spectrometer detector was used. The measured reactive uptake coefficient shows a strong dependence on temperature at constant H 2 O partial pressure. Our results for NAT are qualitatively similar to but quantitatively different from those of Abbatt and Molina [1992 a ]. The hydrolysis of N 2 O 5 and ClONO 2 on frozen sulfuric acid were measured to be far less efficient than that in liquid solutions. The implications of these results to the heterogeneous chemistry of the stratosphere are discussed.