Calcular El Ph De Nh3 Ac 0.10 Mol L

Introduction

The NH3/AC buffer system is a classic example of a weak base (NH3) and a weak acid (CH3COOH) that can maintain a relatively constant pH when small amounts of acid or base are added. This property makes buffer solutions crucial in laboratory settings and biological systems.

To calculate the pH of a buffer solution, we use the Henderson-Hasselbalch equation, which relates the pH to the ratio of the concentrations of the conjugate base to the conjugate acid.

How to Calculate the pH

Calculating the pH of a buffer solution involves several steps:

1. Determine the concentrations of the weak base (NH3) and the weak acid (CH3COOH)
2. Calculate the pKa values for both components
3. Apply the Henderson-Hasselbalch equation
4. Solve for pH using the appropriate values

Our calculator automates these steps for a 0.10 mol/L NH3/AC buffer solution, providing you with an accurate pH value in seconds.

The Formula

The Henderson-Hasselbalch equation is the foundation for buffer pH calculations:

Where:

• pH is the negative logarithm of the hydrogen ion concentration
• pKa is the negative logarithm of the acid dissociation constant
• [A^-] is the concentration of the conjugate base (NH3)
• [HA] is the concentration of the conjugate acid (CH3COOH)

For a 0.10 mol/L NH3/AC buffer solution, we use standard pKa values for NH3 (9.25) and CH3COOH (4.76).

Worked Example

Let's calculate the pH of a 0.10 mol/L NH3/AC buffer solution:

1. Given: [NH3] = 0.10 mol/L, [CH3COOH] = 0.10 mol/L
2. pKa(NH3) = 9.25, pKa(CH3COOH) = 4.76
3. Apply the Henderson-Hasselbalch equation:

   pH = pKa(NH3) + log₁₀([NH3]/[CH3COOH])

4. Substitute the values:

   pH = 9.25 + log₁₀(0.10/0.10) = 9.25 + log₁₀(1) = 9.25 + 0 = 9.25

The calculated pH of this buffer solution is 9.25.