Dissociation of HCl Behind Shock Waves

The dissociation of HCl in HCl–Ar mixtures was studied behind incident shock waves over the temperature range 2900°–4000° using vacuum ultraviolet absorption spectroscopy. The experiments were conducted using gas mixtures of 1% HCl–99% Ar and 2% HCl–98% Ar. For the reaction HCl + Ar→H + Cl + Ar, a rate constant k1 = 4.2 × 1013 exp (− 81 000/RT) cm3mole·sec gave the best fit of the experimental data. This result agrees with the results obtained by Fishburne and Jacobs et al. using infrared emission spectroscopy. The apparent activation energy for HCl dissociation was found to be less than the dissociation energy.