Borax is correctly represented as `Na_(2)[B_(4)O_(5)(OH)_(4)]. 8H_(2)O`. How many tetrahedral boron atoms are present in the structure of
borax?

Answer

To determine the number of tetrahedral boron atoms in the structure of borax, we will analyze the given chemical formula and the structure of the boron atoms.

### Step-by-Step Solution:

1. **Identify the Chemical Formula**:
The chemical formula for borax is given as `Na2[B4O5(OH)4]·8H2O`. This can also be represented as `Na2B4O7·10H2O`.

2. **Understand the Boron Structure**:
In the formula `B4O5(OH)4`, we have 4 boron (B) atoms. We need to determine how many of these are tetrahedral.

3. **Draw the Structure**:
To visualize the arrangement of boron atoms, we can draw the structure of the tetranuclear unit. This unit consists of four boron atoms connected by oxygen atoms.

4. **Identify Hybridization**:
- In the structure, some boron atoms are connected to three other atoms (trigonal planar), and some are connected to four atoms (tetrahedral).
- The boron atoms that are connected to four atoms exhibit sp³ hybridization, which corresponds to a tetrahedral geometry.
- The boron atoms connected to three atoms exhibit sp² hybridization, which corresponds to a trigonal planar geometry.

5. **Count Tetrahedral Boron Atoms**:
- From the structure, we can identify that there are 2 boron atoms that are tetrahedral (sp³ hybridized) and 2 boron atoms that are trigonal planar (sp² hybridized).
- Therefore, the total number of tetrahedral boron atoms in the structure of borax is **2**.

### Final Answer:
The number of tetrahedral boron atoms present in the structure of borax is **2**.

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