Question

Blood $pH$ is controlled by the concentrations of $H_{2}C{O}_3$ and $HC{O}_3{}^{-}$. In the presence of $NaHC{O}_3$, $pH$ of blood:

• A. increases
• B. decreases
• C. does not change
• D. first decreases and then increases

Answer 1

The correct option is A increases

Acidic buffer solution is prepared by mixing a weak acid and its salt with a strong base.
Thus, a mixture of $H_{2}C{O}_3$ and $HC{O}_3^{-}$ acts as an acidic buffer solution.
The expression for the pH of the acidic buffer solution is as given below:
$pH=p{K}_a+log\frac{\left[salt\right]}{\left[acid\right]}$
In the presence of $NaHC{O}_3$, the concentration of salt increases. Hence, the term $log\frac{\left[salt\right]}{\left[acid\right]}$ increases. This increases the $pH$ of blood.