The correct formula of borax is

Options

A. `Na_(2)[B_(4)O_(4)(OH)_(3)].9H_(2)O`
B. `Na_(2)[B_(4)O_(5)(OH)_(4)].8H_(2)O`
C. `Na_(2)[B_(4)O_(6)(OH)_(5)].7H_(2)O`
D. `Na_(2)[B_(4)O_(7)(OH)_(6)].6H_(2)O`

Explanation

To determine the correct formula of borax, we can follow these steps:

### Step 1: Understand Borax
Borax is a compound that is commonly used in various applications, including as a cleaning agent and in glass and ceramics.

### Step 2: Identify the Empirical Formula
The empirical formula of borax is typically represented as Na2B4O7·10H2O. This indicates that borax consists of sodium (Na), boron (B), oxygen (O), and water molecules (H2O).

### Step 3: Write the Proper Formula
While the empirical formula is useful, the proper formula of borax can also be represented in a different way. The proper formula is Na2B4O5(OH)4·8H2O. This representation includes hydroxide ions (OH) and indicates that there are 8 water molecules associated with the compound.

### Step 4: Check the Options
Now, we need to check the provided options to find the correct formula. Based on the proper formula derived, we look for the option that matches Na2B4O5(OH)4·8H2O.

### Step 5: Conclusion
Upon reviewing the options, we find that option 2 corresponds to the correct formula of borax, which is Na2B4O5(OH)4·8H2O.

### Final Answer
The correct formula of borax is **Na2B4O5(OH)4·8H2O**.

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