How does the Hb act as buffer?

The partial pressure of carbon dioxide $\left(\mathrm{ppCO}_2\right)$ of blood entering the pulmonary capillaries is_______.

Haemoglobin has maximum affinity for

Select INCORRECT statements with respects transport of $\mathrm{CO}_2$ by RBCs and plasma.

i. $23 \%$ of $\mathrm{CO}_2$ released from tissue cells diffuse into plasma first and then into RBCs.

ii. Within RBCs carbonic acid immediately dissociates into $\mathrm{H}^{+}$and $\mathrm{HCO}_3^{-}$.

iii. In RBCs $\mathrm{CO}_2$ combines with $\mathrm{H}_2 \mathrm{O}$ to form carbonic acid.

iv. $\mathrm{H}^{+}$ions move out of RBCs and combine with $\mathrm{Na}^{+}$to form $\mathrm{NaHCO}_3$.

v. $7 \%$ of $\mathrm{CO}_2$ is transported in dissolved form as carbonic acid in plasma.

In the light of above statements choose the correct answer from option given below.