A solution contains 0.408 M sodium acetate and 0.145 M acetic acid. The pH of this solution is

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**Buffer Solution pH Calculation**

A buffer solution contains **0.408 M sodium acetate** and **0.145 M acetic acid**.

The pH of this solution is [ _ ].

---

To find the pH of this buffer solution, you can use the Henderson-Hasselbalch equation:

\[ \text{pH} = \text{p}K_a + \log \left(\frac{[\text{A}^-]}{[\text{HA}]}\right) \]

Where:
- \([\text{A}^-]\) is the concentration of the conjugate base (sodium acetate).
- \([\text{HA}]\) is the concentration of the weak acid (acetic acid).
- \(\text{p}K_a\) is the negative logarithm (base 10) of the acid dissociation constant \(K_a\) of the weak acid.

Given that acetic acid (\(\text{CH}_3\text{COOH}\)) has a \(K_a\) value of approximately \(1.8 \times 10^{-5}\), we can calculate \(\text{p}K_a\) as follows:

\[ \text{p}K_a = -\log (1.8 \times 10^{-5}) \approx 4.74 \]

Using the provided concentrations:

\[ \text{pH} = 4.74 + \log \left(\frac{0.408}{0.145}\right) \]

Insert these values into the equation to find the pH of the solution.
Transcribed Image Text:**Buffer Solution pH Calculation** A buffer solution contains **0.408 M sodium acetate** and **0.145 M acetic acid**. The pH of this solution is [ _ ]. --- To find the pH of this buffer solution, you can use the Henderson-Hasselbalch equation: \[ \text{pH} = \text{p}K_a + \log \left(\frac{[\text{A}^-]}{[\text{HA}]}\right) \] Where: - \([\text{A}^-]\) is the concentration of the conjugate base (sodium acetate). - \([\text{HA}]\) is the concentration of the weak acid (acetic acid). - \(\text{p}K_a\) is the negative logarithm (base 10) of the acid dissociation constant \(K_a\) of the weak acid. Given that acetic acid (\(\text{CH}_3\text{COOH}\)) has a \(K_a\) value of approximately \(1.8 \times 10^{-5}\), we can calculate \(\text{p}K_a\) as follows: \[ \text{p}K_a = -\log (1.8 \times 10^{-5}) \approx 4.74 \] Using the provided concentrations: \[ \text{pH} = 4.74 + \log \left(\frac{0.408}{0.145}\right) \] Insert these values into the equation to find the pH of the solution.
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