A solution is prepared at 25 °C that is initially 0.11 M in propanoic acid (HC₂H₂CO₂), a weak acid with K=1.3 × 10¯5, and 0.24M in sodium propanoate (NaC₂H-CO₂). Calculate the pH of the solution. Round your answer to 2 decimal places. pH = 0

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### pH Calculation of a Buffer Solution

**Problem Statement:**

A solution is prepared at 25 °C that is initially \(0.11 \, M\) in propanoic acid \((HC_3H_5CO_2)\), a weak acid with \(K_a = 1.3 \times 10^{-5}\), and \(0.24 \, M\) in sodium propanoate \((NaC_3H_5CO_2)\). Calculate the pH of the solution. Round your answer to 2 decimal places.

**Solution:**

*Graphic*: There is a textbox for entering the pH value, and two buttons marked "x" (possibly to clear the input) and "↻" (likely to reset the task).

---

**Explanation:**

In this scenario, you have a buffer system consisting of a weak acid (propanoic acid) and its conjugate base (sodium propanoate). To calculate the pH of this buffer solution, you can use the Henderson-Hasselbalch equation, which is given by:

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

Where:
- \(\text{p}K_a\) is the negative logarithm of the acid dissociation constant (\(K_a\)): \(\text{p}K_a = -\log(K_a)\)
- \([\text{A}^-]\) is the concentration of the conjugate base (sodium propanoate)
- \([\text{HA}]\) is the concentration of the weak acid (propanoic acid)

1. Calculate \(\text{p}K_a\):
   \[ \text{p}K_a = -\log(1.3 \times 10^{-5}) \approx 4.89 \]

2. Using the concentrations given:
   - \([\text{A}^-] = 0.24 \, M\)
   - \([\text{HA}] = 0.11 \, M\)
   
3. Substitute these values into the Henderson-Hasselbalch equation:
   \[ \text{pH} = 4.89 + \log \left( \frac{0.24}{0.11
Transcribed Image Text:### pH Calculation of a Buffer Solution **Problem Statement:** A solution is prepared at 25 °C that is initially \(0.11 \, M\) in propanoic acid \((HC_3H_5CO_2)\), a weak acid with \(K_a = 1.3 \times 10^{-5}\), and \(0.24 \, M\) in sodium propanoate \((NaC_3H_5CO_2)\). Calculate the pH of the solution. Round your answer to 2 decimal places. **Solution:** *Graphic*: There is a textbox for entering the pH value, and two buttons marked "x" (possibly to clear the input) and "↻" (likely to reset the task). --- **Explanation:** In this scenario, you have a buffer system consisting of a weak acid (propanoic acid) and its conjugate base (sodium propanoate). To calculate the pH of this buffer solution, you can use the Henderson-Hasselbalch equation, which is given by: \[ \text{pH} = \text{p}K_a + \log \left( \frac{[\text{A}^-]}{[\text{HA}]} \right) \] Where: - \(\text{p}K_a\) is the negative logarithm of the acid dissociation constant (\(K_a\)): \(\text{p}K_a = -\log(K_a)\) - \([\text{A}^-]\) is the concentration of the conjugate base (sodium propanoate) - \([\text{HA}]\) is the concentration of the weak acid (propanoic acid) 1. Calculate \(\text{p}K_a\): \[ \text{p}K_a = -\log(1.3 \times 10^{-5}) \approx 4.89 \] 2. Using the concentrations given: - \([\text{A}^-] = 0.24 \, M\) - \([\text{HA}] = 0.11 \, M\) 3. Substitute these values into the Henderson-Hasselbalch equation: \[ \text{pH} = 4.89 + \log \left( \frac{0.24}{0.11
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