Ostwald's dilution law is applicable to

Options

A. Strong electrolytes only
B. Weak electrolytes only
C. Non-electrolytes
D. Strong as well as weak electrolytes.

Explanation

**Step-by-Step Solution:**

1. **Understanding Ostwald's Dilution Law**: Ostwald's dilution law is a principle that applies to weak electrolytes. It describes how the degree of dissociation of a weak electrolyte changes with dilution.

2. **Identifying the Types of Electrolytes**: Electrolytes can be classified into three categories: strong electrolytes, weak electrolytes, and non-electrolytes. Strong electrolytes completely dissociate in solution, while weak electrolytes only partially dissociate.

3. **Application of the Law**: The law is based on the equilibrium established in a weak electrolyte solution. For a weak acid (HA), the dissociation can be represented as:
\[ HA \rightleftharpoons H^+ + A^- \]
The equilibrium constant (K_a) for this dissociation is given by:
\[ K_a = \frac{[H^+][A^-]}{[HA]} \]

4. **Degree of Dissociation**: The degree of dissociation (α) is defined as the fraction of the initial concentration (C) that dissociates. Thus, at equilibrium:
- Concentration of \( H^+ \) = \( Cα \)
- Concentration of \( A^- \) = \( Cα \)
- Concentration of \( HA \) = \( C(1 - α) \)

5. **Deriving the Ostwald's Dilution Law Equation**: Substituting these values into the expression for \( K_a \):
\[ K_a = \frac{(Cα)(Cα)}{C(1 - α)} = \frac{Cα^2}{1 - α} \]
For very dilute solutions, where \( α \) is small, we can approximate \( 1 - α \) as \( 1 \):
\[ K_a \approx \frac{Cα^2}{1} = Cα^2 \]

6. **Conclusion**: Since Ostwald's dilution law is derived from the behavior of weak electrolytes, it is applicable only to weak electrolytes. Therefore, the correct answer to the question is **weak electrolytes**.

**Final Answer**: Ostwald's dilution law is applicable to **weak electrolytes**.

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