Question

The pH of blood is maintained by $C{{O}_{2}}$ and ${{H}_{2}}C{{O}_{3}}$in the body and chemical constituents of blood. This phenomenon is called:
(A) colloidal
(B) buffer actionS
(C) acidity
(D) salt balance

Answer 1

Hint: An aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa is known as a Buffer solution. Buffer solutions can resist pH change.

Complete step by step solution:
-Buffer solutions are used as a means of keeping the pH value nearly constant in a variety of chemical applications.
-Buffering is an important reaction in living systems as a means of maintaining a fairly constant internal environment.
-Small molecules present in the body such as bicarbonate and phosphate provide the buffering capacity to haemoglobin and other proteins.
-There are four main naturally-occurring buffer systems in the body, those are Bicarbonate buffer, Phosphate buffer, Hemoglobin buffer, and Protein buffer.
-Buffering system of blood involves a carbonic acid $({{H}_{2}}C{{O}_{3}})$and uses a Bicarbonate buffer $(HC{{O}_{3}}^{-})$ mechanism. Maintaining a constant blood pH is critical for the proper functioning of enzymes and other mechanisms in the body.
-When an acidic substance enters the bloodstream, the bicarbonate ions neutralize the hydronium ions by forming carbonic acid and water from it. Carbonic acid is already a component of the buffering system of blood, thus hydronium ions are removed from the blood, preventing the pH of blood from becoming acidic.
$HC{{O}_{3}}^{-}+{{H}_{3}}{{O}^{+}}\to {{H}_{2}}C{{O}_{3}}+{{H}_{2}}O$
-When any basic substance enters the bloodstream, the carbonic acid reacts with the hydroxide ions forming bicarbonate ions and water. Bicarbonate ions are already present as a component of the buffer and in this way, the hydroxide ions are removed from the blood, preventing the pH of blood from becoming basic.
${{H}_{2}}C{{O}_{3}}+O{{H}^{-}}\to HC{{O}_{3}}^{-}+{{H}_{2}}O$
-Hence with the help of bicarbonate buffer, the pH of the blood is maintained between 7.35 and 7.45, as a value higher than 7.8 or lower than 6.8 can lead to death.

So, the correct answer is option (B).

Note: Why is it so critical for maintaining the pH of our blood? Our body is so sensitive to a range of pH and temperatures. If the pH of the blood falls below 6.8 or raises above 7.8, the cells of the body can stop functioning, and eventually the person can die. Enzymes are very specific and function optimally at the right temperature and right pH. If the temperature or pH range goes unbalanced, then the denaturing of enzymes occurs, thus disabling their catalytic activity. This in turn affects almost all biological processes in the human body, leading to various diseases and even death in severe cases.