Temperature effect on carbonic acid balance in water

Carbonic acid balance at 0～100℃ is studied based on theoretical analysis and calculation. Proportion and distribution of H2CO3*，HCO3－ and CO32－ in water at different temperature and pH value are elucidated. It is believed that the pH0 ranges slight, between 8.60～8.22 within 0～100℃, and that the proportion of three carbonates accounting for different ratios with the changes of the pH, but the difference is small. At any temperature between 0℃ and 100℃, H2CO3* dominates in acidic water, while CO32－ in alkaline water and HCO3－ in low acidic, low alkaline and neutral water. It is difficult for CO32－ determination with traditional method for its low concentration under low pH value.