To determine if a solution of [tex]\( H_2CO_3 \)[/tex] (carbonic acid) and [tex]\( NaHCO_3 \)[/tex] (sodium bicarbonate) would function well as a buffer, we need to understand what a buffer solution is and how it works.
### Buffer Solution:
A buffer solution is a mixture that can resist changes in pH when small quantities of an acid or base are added to it. Typically, a buffer solution consists of:
1. A weak acid and its conjugate base, or
2. A weak base and its conjugate acid.
### Components in Question:
1. [tex]\( H_2CO_3 \)[/tex] (Carbonic acid): This is a weak acid.
2. [tex]\( NaHCO_3 \)[/tex] (Sodium bicarbonate): This is a salt that provides the conjugate base [tex]\( HCO_3^- \)[/tex] (bicarbonate ion) when it dissolves in water.
### Functioning of Buffer:
For a buffer solution to effectively resist changes in pH, it should have:
- Sufficient amounts of both the weak acid (to neutralize added base).
- Sufficient amounts of the conjugate base (to neutralize added acid).
### How This Particular Solution Works:
- [tex]\( H_2CO_3 \)[/tex] (Carbonic acid) will dissociate slightly to produce [tex]\( H^+ \)[/tex] ions and [tex]\( HCO_3^- \)[/tex] (bicarbonate ions), the latter acting as the conjugate base.
[tex]\[ H_2CO_3 \rightleftharpoons H^+ + HCO_3^- \][/tex]
- [tex]\( NaHCO_3 \)[/tex] (Sodium bicarbonate), when dissolved in water, dissociates completely to provide [tex]\( Na^+ \)[/tex] ions and additional [tex]\( HCO_3^- \)[/tex] ions.
[tex]\[ NaHCO_3 \rightarrow Na^+ + HCO_3^- \][/tex]
The resulting mixture will contain both [tex]\( H_2CO_3 \)[/tex] (the weak acid) and [tex]\( HCO_3^- \)[/tex] (the conjugate base). Therefore, this system can neutralize small amounts of added acid (by the bicarbonate ion) or base (by the carbonic acid), thus maintaining the pH.
### Conclusion:
Yes, a solution of [tex]\( H_2CO_3 \)[/tex] and [tex]\( NaHCO_3 \)[/tex] would function well as a buffer because it contains both the weak acid (carbonic acid) and its conjugate base (bicarbonate ion), which are necessary components to resist pH changes.
