How many moles of `HCl` will be required to completely convert `1` moles of borax into borax acid ?

Options

A. 1
B. 2
C. 3
D. none of these

Explanation

To determine how many moles of HCl are required to completely convert 1 mole of borax (Na2B4O7·10H2O) into boric acid (H3BO3), we can follow these steps:

### Step 1: Write the chemical reaction
The reaction between borax and hydrochloric acid can be represented as follows:

\[ \text{Na}_2\text{B}_4\text{O}_7 + \text{HCl} + \text{H}_2\text{O} \rightarrow \text{H}_3\text{BO}_3 + \text{NaCl} \]

### Step 2: Balance the chemical equation
We need to balance the equation to find out how many moles of HCl are needed. The unbalanced equation is:

\[ \text{Na}_2\text{B}_4\text{O}_7 + \text{HCl} + \text{H}_2\text{O} \rightarrow \text{H}_3\text{BO}_3 + \text{NaCl} \]

1. **Sodium (Na)**: There are 2 Na in borax, so we need 2 NaCl.
2. **Boron (B)**: There are 4 B in borax, so we need 4 H3BO3.
3. **Chlorine (Cl)**: Since we have 2 NaCl, we need 2 HCl.
4. **Hydrogen (H)**: We have 4 H from 4 H3BO3 and 2 from HCl, totaling 12 H on the left side when we consider the water.

The balanced equation will look like this:

\[ \text{Na}_2\text{B}_4\text{O}_7 + 2 \text{HCl} + 2 \text{H}_2\text{O} \rightarrow 4 \text{H}_3\text{BO}_3 + 2 \text{NaCl} \]

### Step 3: Determine the moles of HCl required
From the balanced equation, we see that 1 mole of borax reacts with 2 moles of HCl. Therefore, to convert 1 mole of borax into boric acid, we need:

\[ \text{2 moles of HCl} \]

### Conclusion
Thus, the number of moles of HCl required to completely convert 1 mole of borax into boric acid is **2 moles**.

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