When sulfur trioxide is used in the commercial production of sulfuric acid, one part of the process is to first dissolve it in sulfuric acid which produces a fuming liquid with the molecular formula H2S2O7. This liquid is then diluted with water to form liquid .sulfuric acid, H2SO4, as the only product in the reaction
(i) Write a balanced chemical equation for the formation of sulfuric acid from H2S2O7 when diluted with water.
(ii) State whether sulfuric acid is a strong or weak acid and write a fully balanced chemical equation for the dissociation of sulfuric acid in aqueous solution. Hence, calculate the pH of a 2.55 × 10-3 mol dm-3 aqueous solution of sulfuric acid. (Show all your working in your calculation and give your final answer to two significant figures.)