When `Al` is added to sodium hydroxide solution:

Options

A. no reaction takes place
B. oxygen is evolved
C. water is produced
D. hydrogen is evolved

Explanation

To solve the question of what happens when aluminum (Al) is added to sodium hydroxide (NaOH) solution, we can follow these steps:

### Step 1: Write the Reactants
We start with the reactants involved in the reaction:
- Aluminum (Al)
- Sodium Hydroxide (NaOH)
- Water (H2O)

### Step 2: Identify the Reaction
Aluminum reacts with sodium hydroxide in the presence of water. The reaction can be represented as follows:
\[ 2 \text{Al} + 2 \text{NaOH} + 6 \text{H}_2\text{O} \rightarrow 2 \text{[Al(OH)}_4]^{-} + 2 \text{Na}^{+} + 3 \text{H}_2 \]

### Step 3: Analyze the Products
From the balanced equation, we can see that the products of the reaction include:
- Sodium tetrahydroxoaluminate \([Al(OH)_4]^{-}\)
- Sodium ions (\(Na^{+}\))
- Hydrogen gas (\(H_2\))

### Step 4: Conclusion
The key observation from the reaction is that hydrogen gas is evolved. Therefore, when aluminum is added to sodium hydroxide solution, hydrogen is emitted.

### Final Answer
When aluminum is added to sodium hydroxide solution, hydrogen gas is evolved.

---