Question

Which one of the following is natural buffer ?

• A. Blood
• B. River water
• C. (a) and (b) above.
• D. None of the above

Answer 1

The correct option is C (a) and (b) above.

Human blood contains a buffer of Carbonic acid $\left(H_{2}C{O}_3\right)$ and bicarbonate anion $\left(HC{O}_3^{-}\right)$. Whenever any acidic substance enters the blood, the bicarbonate ions neutralize the hydronium ions forming carbonic acid and water. Thus hydronium ions are removed preventing the $pH$ of blood from becoming acid.
River water prevents localized change in $pH$ as a result of which no change may be measured under natural condition.
Hence both blood and river water are natural buffer.