`pK_(a)` and `K_(a)` of an acid are connected by the relation.......

Answer

To find the relationship between \( pK_a \) and \( K_a \) of an acid, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding \( K_a \)**:
- The \( K_a \) (acid dissociation constant) is a measure of the strength of an acid in solution. It quantifies how well an acid donates protons (H⁺) to water.
- For a generic acid \( HA \) dissociating into \( H^+ \) and \( A^- \):
\[ HA \rightleftharpoons H^+ + A^- \]
- The expression for \( K_a \) is given by:
\[ K_a = \frac{[H^+][A^-]}{[HA]} \]

2. **Defining \( pK_a \)**:
- The \( pK_a \) is the negative logarithm of the \( K_a \):
\[ pK_a = -\log(K_a) \]

3. **Establishing the Relationship**:
- From the definition of \( pK_a \), we can express the relationship between \( pK_a \) and \( K_a \):
\[ pK_a = -\log(K_a) \]
- This indicates that as the \( K_a \) value increases (indicating a stronger acid), the \( pK_a \) value decreases.

4. **Interpreting the Relationship**:
- A higher \( K_a \) means a stronger acid, which corresponds to a lower \( pK_a \). Conversely, a weaker acid has a lower \( K_a \) and a higher \( pK_a \).
- Therefore, the relationship can be summarized as:
\[ pK_a \text{ and } K_a \text{ are inversely related.} \]

### Final Answer:
The relationship between \( pK_a \) and \( K_a \) of an acid is given by:
\[ pK_a = -\log(K_a) \]