When sodium hydroxide reacts with aluminium metal:A. Sodium aluminate and water gas are formed.B. Sodium aluminate and hydrogen gas are formed.C. No reactionD. Can’t say

To solve the question about the reaction between sodium hydroxide (NaOH) and aluminium (Al) metal, let's break it down step by step.

**Reaction Overview:**

When sodium hydroxide reacts with aluminium, a chemical reaction occurs. The balanced equation for this reaction can be represented as follows:

\[ 2 \, \text{NaOH} + 2 \, \text{Al} + 6 \, \text{H}_2\text{O} \rightarrow 2 \, \text{NaAl(OH)}_4 + 3 \, \text{H}_2 \]

**Details of the Reaction:**

1. **Reactants:**
- Sodium hydroxide (NaOH) is a strong base.
- Aluminium (Al) is a reactive metal.

2. **Products:**
- Sodium aluminate (\( \text{NaAl(OH)}_4 \)) is formed as a result of the reaction.
- Hydrogen gas (\( \text{H}_2 \)) is released during the reaction.

3. **Mechanism:**
- Aluminium reacts with hydroxide ions (\( \text{OH}^- \)) from sodium hydroxide.
- This reaction typically produces sodium aluminate and hydrogen gas.

4. **Conditions:**
- The reaction usually requires the presence of water to facilitate the interaction between sodium hydroxide and aluminium.

**Conclusion:**

From the above analysis, the correct answer to the question is:
**B. Sodium aluminate and hydrogen gas are formed.**