Question

S-I: Blood is a buffer solution, whose pH is maintained at 7.4 by an acidic buffer. 
S-II: pH is maintained by HCO₃^-  and   H₂CO₃

• A. S-I and S-II both are correct
• B. S-I and S-II both in correct
• C. S-I is correct and S-II are incorrect
• D. S-I is incorrect and S-II is correct

Answer 1

The Correct Option is A

To determine the correctness of the statements given, we need to analyze each statement independently.

1. Statement I (S-I): Blood is a buffer solution, whose pH is maintained at 7.4 by an acidic buffer.
   • A buffer solution is one that resists changes in pH upon the addition of small amounts of acid or base. Blood indeed acts as a buffer solution.
   • In the human body, the pH of blood is tightly regulated around 7.4, which is slightly alkaline.
   • The primary buffer system in blood is the bicarbonate buffer system.
   • Therefore, Statement I is correct.
2. Statement II (S-II): pH is maintained by \text{HCO}_3^-\ and \text{H}_2\text{CO}_3\.
   • The bicarbonate buffer system in blood involves the equilibrium between bicarbonate ions (\text{HCO}_3^-\) and carbonic acid (\text{H}_2\text{CO}_3).
   • This system is crucial in maintaining the pH of blood as it can neutralize small amounts of added acid or base.
   • This buffer system is effective in regulating the pH around 7.4, which matches the physiological pH of blood.
   • Therefore, Statement II is correct.

In conclusion, both Statement I and Statement II are correct. Blood acts as a buffer solution, and the bicarbonate buffer system efficiently maintains the blood pH at approximately 7.4 by managing the concentrations of bicarbonate ions and carbonic acid.