Explanation

$\mathbf{C}\mathbf{O}_{\mathbf{2}}\mathbf{\ Transport}$ Transport of $CO_{2}$ by blood is much easier than oxygen due to high solubility of $CO_{2}$. About 7% of $CO_{2}$ is transported dissolved in plasma, 23% loosely bind with the haemoglobin and forms bicarbonates and about 70% of $CO_{2}$ reacts with water to form carbonic acid in erythrocytes in the presence of enzyme carbonic anhydrase. The carbonic acid $(H_{2}CO_{3})$ dissociates into $H^{+}$ and $HCO_{3}^{-}$ ions $CO_{2} + H_{2}O\overset{\ \ Carbonic\ Anhydrase\ \ }{\rightarrow}\ H_{2}CO_{3} \rightleftharpoons HCO_{3}^{-} + H^{+}$