Given below are two statements : Statement (I) : A Buffer solution is the mixture of a salt and an acid or a base mixed in any particular quantities. Statement (II) : Blood is naturally occurring buffer solution whose pH is maintained by $$H_2CO_3/HCO_3^-$$ concentrations. In the light of the above statements, choose the correct answer from the options given below :

We need to evaluate two statements about buffer solutions.

Analysis of Statement (I): "A Buffer solution is the mixture of a salt and an acid or a base mixed in any particular quantities."

This statement is FALSE. While a buffer solution is indeed a mixture of a weak acid and its conjugate base (or a weak base and its conjugate acid), it does not work with just "any" quantities. For a buffer to function effectively, the components must be mixed in appropriate proportions. Specifically:

- The buffer capacity depends on the ratio of the concentrations of the conjugate pair.

- An effective buffer typically has a pH within one unit of the $$pK_a$$ of the weak acid, which requires the ratio $$[salt]/[acid]$$ to be between 0.1 and 10.

- If the ratio is too extreme, the solution will not resist pH changes effectively.

Analysis of Statement (II): "Blood is naturally occurring buffer solution whose pH is maintained by $$H_2CO_3/HCO_3^-$$ concentrations."

This statement is TRUE. Blood is a naturally occurring buffer that maintains its pH around 7.4. The primary buffer system in blood is the carbonic acid-bicarbonate buffer system:

$$H_2CO_3 \rightleftharpoons H^+ + HCO_3^-$$

When excess acid ($$H^+$$) enters the blood, bicarbonate ions ($$HCO_3^-$$) neutralise it. When excess base ($$OH^-$$) enters, carbonic acid ($$H_2CO_3$$) neutralises it. This maintains the blood pH within a narrow, life-sustaining range.

The correct answer is Option (3): Statement I is false but Statement II is true.