van't Hoffer factor for acetic acid in aqueos medium at infinite dilution is

Options

A. 2
B. 1
C. `1//2`
D. 3

Answer

To determine the van't Hoff factor (i) for acetic acid (CH₃COOH) in aqueous medium at infinite dilution, we can follow these steps:

### Step 1: Understand the Concept of van't Hoff Factor
The van't Hoff factor (i) is a measure of the number of particles into which a solute dissociates in solution. For a non-electrolyte, i = 1, while for electrolytes, it can be greater than 1 depending on the degree of dissociation.

### Step 2: Identify the Nature of Acetic Acid
Acetic acid (CH₃COOH) is a weak acid and partially dissociates in water. The dissociation can be represented as:
\[ \text{CH}_3\text{COOH} \rightleftharpoons \text{CH}_3\text{COO}^- + \text{H}^+ \]

### Step 3: Determine the Degree of Dissociation (α)
At infinite dilution, the degree of dissociation (α) approaches 1, meaning that almost all of the acetic acid molecules dissociate into ions.

### Step 4: Calculate the Number of Particles (n)
In the dissociation of acetic acid, one molecule of acetic acid produces two ions:
1. Acetate ion (CH₃COO⁻)
2. Hydrogen ion (H⁺)

Thus, n = 2 (the number of particles formed from one molecule of acetic acid).

### Step 5: Apply the van't Hoff Factor Formula
The formula for calculating the van't Hoff factor (i) for dissociation is:
\[ i = 1 + (n - 1) \cdot \alpha \]

Substituting the values:
- n = 2
- α = 1 (at infinite dilution)

We get:
\[ i = 1 + (2 - 1) \cdot 1 \]
\[ i = 1 + 1 \]
\[ i = 2 \]

### Conclusion
The van't Hoff factor (i) for acetic acid in aqueous medium at infinite dilution is 2.

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