Question

why the higher percentage of co2 transported by water of RBC as compared to water of plasma ? also give the equation of this process.

Answer 1

About 5-7% of all carbon dioxide is dissolved in the plasma. The remaining 93% diffuses into RBC (where 70% exist as bicarbonate ions and 23% binds to hemoglobin forming Hb-CO2). This affinity to RBC is explained by the abundance of carbonic anhydrase enzyme there. The latter one catalyzes the reaction between CO2 and H2O. 

Hb + CO2 = Hb · CO2 (Carbaminohemoglobin)