A buffer is made by dissolving HC2H3O2 and NaC2H3O2 in water. Write an equation that shows how this buffer neutralizes added acid. Express your answer as a chemical equation. Identify all of the phases in the answer.
The equation for how the buffer neutralizes added acid can be represented as follows:
HC2H3O2 (aq) + H+ (aq) ⟷ H2C2H3O2+ (aq)
In this equation, HC2H3O2 represents acetic acid, and H+ represents the added acid. The arrows indicate a reversible reaction, meaning that the reaction can go in both directions. The product on the right side, H2C2H3O2+, is the conjugate acid of the weak base acetate, C2H3O2-. The "+" indicates a positive charge.
The phases in the equation are:
HC2H3O2 (aq): The acetic acid is in the aqueous phase, meaning it is dissolved in water.
H+ (aq): The added acid is also in the aqueous phase.
H2C2H3O2+ (aq): The conjugate acid, formed from the reaction between acetic acid and the added acid, is also in the aqueous phase.
To write the equation that shows how the buffer neutralizes added acid, let's first understand the components involved. In this case, the buffer is made by dissolving HC2H3O2 (acetic acid) and NaC2H3O2 (sodium acetate) in water.
When an acid is added to the buffer, it will react with the sodium acetate to form acetic acid and the conjugate base of the acid. The equation representing this process is as follows:
CH3COONa (aqueous) + HX (aqueous) -> CH3COOH (aqueous) + NaX (aqueous)
In this equation:
- CH3COONa represents sodium acetate, which is a salt of acetic acid.
- HX represents the added acid.
- CH3COOH represents acetic acid, which is the acid component of the buffer.
- NaX represents the corresponding salt formed with the added acid.
Remember, the phases are denoted as "aqueous" (aq) for substances dissolved in water.
Note that this equation represents the neutralization of the added acid by the buffer. The buffer system helps maintain a relatively constant pH in the solution by utilizing the conjugate acid-base pair (acetic acid and acetate ion) present in the buffer solution.
You can add the phases.
Ac^- + H^+ ==> HAc