Introduction:

To determine the approximate pH of a solution obtained by mixing 50 ml of 2N acetic acid with 10 ml of 1N sodium acetate, we need to consider the acid-base properties of acetic acid and its conjugate base, acetate.

Acetic Acid (CH3COOH):
- Acetic acid is a weak acid, meaning it only partially dissociates in water.
- It can donate a proton (H+) to water, leading to the formation of hydronium ions (H3O+).
- The dissociation equation for acetic acid is CH3COOH ⇌ CH3COO- + H+.

Sodium Acetate (CH3COONa):
- Sodium acetate is the salt of acetic acid, meaning it is formed when acetic acid reacts with a strong base like sodium hydroxide.
- In water, sodium acetate dissociates completely into sodium ions (Na+) and acetate ions (CH3COO-).
- The dissociation equation for sodium acetate is CH3COONa → CH3COO- + Na+.

Buffer Solution:
- When a weak acid and its conjugate base are present in a solution, they can resist changes in pH when small amounts of acid or base are added.
- This type of solution is called a buffer solution.
- Acetic acid and acetate ions can form a buffer solution when they are present together.

Calculating the Concentration of Acetic Acid and Acetate Ions:
To calculate the concentration of acetic acid and acetate ions in the resulting solution, we can use the formula:

C1V1 = C2V2

Where:
- C1 and V1 are the initial concentration and volume of the acetic acid (2N, 50 ml).
- C2 and V2 are the final concentration and volume of the resulting solution.

Using this formula, we can calculate the final concentration of the acetic acid and acetate ions.

Calculating the pH of the Buffer Solution:
To determine the pH of the buffer solution, we need to consider the dissociation of acetic acid and the equilibrium between the acid and its conjugate base.

The dissociation of acetic acid produces hydronium ions (H3O+), which contribute to the solution's acidity. The equilibrium between acetic acid and acetate ions also plays a role in maintaining the pH of the buffer solution.

The pH of the buffer solution can be calculated using the Henderson-Hasselbalch equation:

pH = pKa + log ([A-]/[HA])

Where:
- pH is the logarithmic measure of the hydrogen ion concentration in the solution.
- pKa is the negative logarithm of the acid dissociation constant of acetic acid.
- [A-] is the concentration of the acetate ions.
- [HA] is the concentration of the undissociated acetic acid.

The pKa value of acetic acid is approximately 4.76.

By substituting the known values into the Henderson-Hasselbalch equation, we can calculate the pH of the buffer solution.

Conclusion:
By considering the acid-base properties of acetic acid and sodium acetate and using the Henderson-Hasselbalch equation, we can determine the approximate