Comparative Study between Carbonic and Sulfurous Acids for Dissociation Reaction

The conversion between carbonic acid and carbon dioxide plus water is of special significance in many biological and geochemical systems. In this work, we give a theoretical comparison study between H 2 CO 3 and H 2 SO 3 for the dissociation reaction in the environment of microsolvation with the size of the water cluster up to three water molecules, H 2 XO 3 + (n‐1)H 2 O ⇌ XO 2 +nH 2 O n = 1, 2, 3 X=C, S From the calculation of B3LYP/6‐31+G, we conclude that H 2 SO 3 is more unstable than H 2 CO 3 kinetically due to a smaller bond angle change of ∠OXO. It is also more unstable thermodynamically due to better solvation for the product XO 2 .