Aqueous solution containing `1` mol of borax raects with `2` mol of acids. This is because of:

Options

A. formation of `2` mol of `B(OH)_(3)` only
B. formation of `2` mol of `[B(OH)_(4)]^(-)` only
C. formation of `1` mol each of `B(OH)_(3)` and `[B(OH)_(4)]^(-)`
D. formation of `2` mol each of `[B(OH)_(4)]^(-)` and `B(OH)_(3)`, of which only `[B(OH)_(4)]^(-)` reacts with acid

Explanation

To solve the question regarding the reaction of borax with acids, we will break down the process step by step.

### Step-by-Step Solution:

1. **Identify Borax Composition**:
- Borax is chemically represented as Na₂B₄O₇·10H₂O (sodium tetraborate decahydrate). In an aqueous solution, it dissociates into sodium ions (Na⁺) and borate ions (B₄O₇²⁻).

2. **Dissociation of Borax**:
- When 1 mole of borax dissolves in water, it dissociates to produce:
- 2 moles of Na⁺
- 1 mole of B₄O₇²⁻

3. **Formation of Boric Acid and Sodium Borate**:
- The borate ions (B₄O₇²⁻) can react with water to form boric acid (H₃BO₃) and sodium borate (NaB(OH)₄). The reaction can be represented as:
- B₄O₇²⁻ + 7H₂O → 4H₃BO₃ + 2NaB(OH)₄
- This indicates that from 1 mole of borax, we can produce 2 moles of sodium borate (NaB(OH)₄) and 2 moles of boric acid (H₃BO₃).

4. **Understanding the Reaction with Acids**:
- Boric acid (H₃BO₃) is a weak acid and does not react further with other acids. However, sodium borate (NaB(OH)₄) can react with acids.
- Therefore, when 2 moles of acid are added to the solution, they will primarily react with the sodium borate (NaB(OH)₄).

5. **Conclusion**:
- The reason why 1 mole of borax reacts with 2 moles of acid is due to the formation of 2 moles of sodium borate (NaB(OH)₄) which can react with the acids, while the boric acid does not participate in further reactions.

### Final Answer:
The aqueous solution containing 1 mole of borax reacts with 2 moles of acids because the sodium borate (NaB(OH)₄) formed from the dissociation of borax reacts with the acids.

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