Give equations when sodium carbonate is added to water.

Explanation

To solve the question of what happens when sodium carbonate is added to water, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
Sodium carbonate is represented as \( \text{Na}_2\text{CO}_3 \) and water is represented as \( \text{H}_2\text{O} \).

2. **Write the Initial Reaction**:
When sodium carbonate is added to water, it reacts as follows:
\[ \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} \rightarrow \text{NaOH} + \text{H}_2\text{CO}_3 \]

3. **Identify the Products**:
The products of this reaction are sodium hydroxide (\( \text{NaOH} \)) and carbonic acid (\( \text{H}_2\text{CO}_3 \)).

4. **Balance the Equation**:
To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides. The balanced equation is:
\[ \text{Na}_2\text{CO}_3 + 2\text{H}_2\text{O} \rightarrow 2\text{NaOH} + \text{H}_2\text{CO}_3 \]

### Final Balanced Equation:
\[ \text{Na}_2\text{CO}_3 + 2\text{H}_2\text{O} \rightarrow 2\text{NaOH} + \text{H}_2\text{CO}_3 \]