Which of the following is formed by the action of water on sodium?

Options

A. `H_2`
B. `CO`
C. `CO_2`
D. `O_2`

Explanation

To determine which substance is formed by the action of water on sodium, we can analyze the chemical reaction that occurs when sodium reacts with water.

### Step-by-Step Solution:

1. **Identify the Reactants**: The reactants in this reaction are sodium (Na) and water (H₂O).

2. **Write the Chemical Equation**: The balanced chemical equation for the reaction between sodium and water is:
\[ 2 \text{Na} + 2 \text{H}_2\text{O} \rightarrow 2 \text{NaOH} + \text{H}_2 \]

3. **Identify the Products**: From the balanced equation, we can see that the products of this reaction are sodium hydroxide (NaOH) and hydrogen gas (H₂).

4. **Characteristics of the Products**:
- Sodium hydroxide (NaOH) is a strong base and is often referred to as caustic soda. It is soluble in water, forming an alkaline solution.
- Hydrogen gas (H₂) is released as a byproduct and is flammable.

5. **Conclusion**: The question asks which substance is formed by the action of water on sodium. Based on the balanced equation, we can conclude that hydrogen gas (H₂) is one of the products formed.

### Final Answer:
The substance formed by the action of water on sodium is **hydrogen gas (H₂)**.

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