`HCO_(3)^(-)` is conjugate base of `H_(2)CO_(3)`.

Answer

To determine whether \( \text{HCO}_3^{-} \) is the conjugate base of \( \text{H}_2\text{CO}_3 \), we can analyze the dissociation of \( \text{H}_2\text{CO}_3 \) (carbonic acid) in water.

### Step-by-Step Solution:

1. **Understanding the Concept of Conjugate Acid-Base Pairs**:
- According to the Brønsted-Lowry theory, an acid is a substance that donates a proton (H\(^+\)), and a base is a substance that accepts a proton. When an acid donates a proton, it forms its conjugate base.

2. **Dissociation of Carbonic Acid**:
- The dissociation of carbonic acid (\( \text{H}_2\text{CO}_3 \)) can be represented as follows:
\[ \text{H}_2\text{CO}_3 \rightleftharpoons \text{H}^+ + \text{HCO}_3^{-} \]
- In this reaction, \( \text{H}_2\text{CO}_3 \) donates a proton (H\(^+\)) to form \( \text{HCO}_3^{-} \) (bicarbonate ion).

3. **Identifying the Conjugate Base**:
- After the dissociation, \( \text{HCO}_3^{-} \) is formed as a result of the loss of a proton from \( \text{H}_2\text{CO}_3 \).
- Therefore, \( \text{HCO}_3^{-} \) is indeed the conjugate base of \( \text{H}_2\text{CO}_3 \).

4. **Conclusion**:
- Since \( \text{HCO}_3^{-} \) is produced when \( \text{H}_2\text{CO}_3 \) donates a proton, we can conclude that the statement "HCO\(_3^{-}\) is the conjugate base of H\(_2\)CO\(_3\)" is true.

### Final Answer:
Yes, \( \text{HCO}_3^{-} \) is the conjugate base of \( \text{H}_2\text{CO}_3 \).

---