The involvement of the H2OCl+ ion in the ClONO2 hydrolysis on an ice surface is shown to be unlikely via quantum chemical calculations and comparative analysis of infrared spectra of low temperature mixtures of H2O with HNO3, N2O5 or ClONO2. For the ClONO2 hydrolysis on ice, the reaction path involving H2OCl+ is estimated to be similar to 10- 14 kcal/mol higher in energy than the one involving H3O+ via proton transfer in the ice lattice. An analysis of literature infrared spectra, complemented by quantum chemical calculations of the vibrational frequencies of the relevant species, indicates that the spectral feature previously assigned to H2OCl+ should instead be assigned to molecular HNO3.