The `pH` of an acidic buffer mixture is:

Options

A. `gt7`
B. `lt7`
C. `=7`
D. Depends upon `K_(a)` of acids

Explanation

To determine the pH of an acidic buffer mixture, we can use the Henderson-Hasselbalch equation, which is a fundamental equation in buffer chemistry. Here’s a step-by-step solution:

### Step 1: Understand the Henderson-Hasselbalch Equation
The pH of an acidic buffer solution can be calculated using the following equation:
\[ \text{pH} = \text{pK}_a + \log\left(\frac{[\text{Salt}]}{[\text{Acid}]}\right) \]
Where:
- \(\text{pH}\) is the pH of the buffer solution.
- \(\text{pK}_a\) is the negative logarithm of the acid dissociation constant (\(K_a\)) of the weak acid in the buffer.
- \([\text{Salt}]\) is the concentration of the salt (the conjugate base).
- \([\text{Acid}]\) is the concentration of the weak acid.

### Step 2: Identify the Components of the Buffer
In an acidic buffer, you typically have a weak acid (HA) and its conjugate base (A⁻, usually in the form of a salt). For example, acetic acid (CH₃COOH) and sodium acetate (CH₃COONa) can form an acidic buffer.

### Step 3: Determine the pK_a Value
The pK_a value is specific to the weak acid used in the buffer. You can find this value in tables of acid dissociation constants. For acetic acid, the pK_a is approximately 4.76.

### Step 4: Calculate the Ratio of Salt to Acid Concentration
To use the Henderson-Hasselbalch equation, you need the concentrations of the salt and the acid. If you have these values, you can calculate the ratio \(\frac{[\text{Salt}]}{[\text{Acid}]}\).

### Step 5: Substitute Values into the Equation
Once you have the pK_a and the ratio of salt to acid, substitute these values into the Henderson-Hasselbalch equation to find the pH.

### Example Calculation
If you have a buffer solution with:
- \([\text{Salt}] = 0.1 \, M\)
- \([\text{Acid}] = 0.05 \, M\)
- \(\text{pK}_a = 4.76\)

You would calculate:
\[ \text{pH} = 4.76 + \log\left(\frac{0.1}{0.05}\right) \]
\[ \text{pH} = 4.76 + \log(2) \]
\[ \text{pH} = 4.76 + 0.301 \]
\[ \text{pH} \approx 5.06 \]

### Conclusion
The pH of the acidic buffer mixture depends on the pK_a of the weak acid and the ratio of the concentrations of the salt and the acid.

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