5% of $C{O}_2$ is dissolved in ___(i)____. Another form in which $C{O}_2$ is transported is when it combines with hemoglobin and this form is called ___(ii)____hemoglobin. $C{O}_2$ entering the erythrocytes reacts with water to form carbonic acid in the presence of ____(iii)_____. Carbonic acid is an intermediate step; it dissociates to form a hydrogen ion $\left(H^{+}\right)$ from the carbonic acid, leaving___(iv)____ dissolved in the blood.

Q. Choose the right sequential phenomena among the following during the delivery of $O_2$ from blood tissue.
P : Absorption of $C{O}_2$ by the blood.
Q : Reaction of absorbed $C{O}_2$ with $H_{2}O$ to form $H_{2}C{O}_3$ within RBC and its conversion into $H^{+}$ and $HC{O}_3^{-}$ ions in the presence of carbonic anhydrase enzyme.
R : Reaction of absorbed $C{O}_2$ with $H_{2}O$ in plasma to form $H_{2}C{O}_3$ and its conversion into $H^{+}$ and $HC{O}_3^{-}$ ions in the presence of carbonic anhydrase enzyme.
S : Combination of $H^{+}$ with heme portion of $Hb{O}_2$ to release $O_2$.
T : Combination of $HC{O}_3^{-}$ with heme portion $Hb{O}_2$ to form reduced hemoglobin and release of $O_2$.

Q. Carbon dioxide entering erythrocytes reacts with water to form carbonic acid. The enzyme catalyzing this

Q. Which of the following statements are true/false?
(1) The blood transports $C{O}_2$ comparatively easily because of its higher solubility.
(2) Approximately 8.9 % of $C{O}_2$ is transported being dissolved in the plasma of blood.
(3) The carbon dioxide produced by the tissues,diffuses passively into the blood stream and passes into red blood corpuscles and react with water to form $H_{2}C{O}_3$.
(4) The oxyhaemoglobin($Hb{O}_2$) of the erythrocytes is basic.
(5) The chloride ions diffuse from plasma into the erythrocytes to maintain ionic balance.

Q. Assertion :When $C{O}_2$ is continuously bubbled through lime water a precipitate is formed which later dissolves. Reason: Calcium carbonate is initially formed which reacts further with carbon dioxide to form calcium bicarbonate.