In the dissociation of bicarbonate ion, the conjugate base involved is :

Options

A. `CO_(3)^(2-)`
B. `CO_(2)`
C. `H_(2)CO_(3)`
D. CO

Explanation

To determine the conjugate base involved in the dissociation of the bicarbonate ion (HCO₃⁻), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Conjugate Base**:
- A conjugate base is formed when an acid donates a proton (H⁺). In simpler terms, when an acid loses a hydrogen ion, the remaining species is its conjugate base.

2. **Identify the Bicarbonate Ion**:
- The bicarbonate ion is represented as HCO₃⁻. This ion can act as an acid by donating a proton.

3. **Dissociation of Bicarbonate Ion**:
- When the bicarbonate ion dissociates, it loses a proton (H⁺):
\[ \text{HCO}_3^- \rightarrow \text{CO}_3^{2-} + \text{H}^+ \]
- Here, HCO₃⁻ donates a proton and transforms into CO₃²⁻ (carbonate ion).

4. **Identify the Conjugate Base**:
- After the dissociation, the species that remains (after losing the proton) is the carbonate ion (CO₃²⁻). Therefore, CO₃²⁻ is the conjugate base of the bicarbonate ion.

5. **Conclusion**:
- The conjugate base involved in the dissociation of bicarbonate ion (HCO₃⁻) is the carbonate ion (CO₃²⁻).

### Final Answer:
The conjugate base involved in the dissociation of bicarbonate ion is **CO₃²⁻ (carbonate ion)**.

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