`H_2CO_3(aq)+H_2O(l)toHCO_3^-(aq) + H_3O^+(aq)`
`HCO_3^(-)(aq) + H_2O(l)to CO_3^(2-)(aq)+H_3O^(+)(aq)`
Accoding to the equations above, what is the conjugate base of `HCO_3^-`?

Options

A. `H_2CO_3(aq)`
B. `H_2O(l)`
C. `H_3O^+(aq)`
D. `CO_3^(2-)(aq)`

Answer

To determine the conjugate base of \( \text{HCO}_3^- \), we can follow these steps:

### Step 1: Understand the concept of conjugate acids and bases
A conjugate base is formed when an acid donates a proton (H⁺). In this case, we need to identify what happens when \( \text{HCO}_3^- \) donates a proton.

### Step 2: Identify the acid in the reaction
From the given reaction:
\[ \text{HCO}_3^- + \text{H}_2\text{O} \rightarrow \text{CO}_3^{2-} + \text{H}_3\text{O}^+ \]
Here, \( \text{HCO}_3^- \) acts as an acid because it donates a proton to water, forming \( \text{H}_3\text{O}^+ \).

### Step 3: Determine the conjugate base
When \( \text{HCO}_3^- \) donates a proton (H⁺), it transforms into \( \text{CO}_3^{2-} \). Therefore, the conjugate base of \( \text{HCO}_3^- \) is the species that remains after the acid has donated a proton.

### Step 4: Conclusion
Thus, the conjugate base of \( \text{HCO}_3^- \) is \( \text{CO}_3^{2-} \).

### Final Answer
The conjugate base of \( \text{HCO}_3^- \) is \( \text{CO}_3^{2-} \).

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