In borax the number of B-O-B links and B-OH bond present are, respectively.

Options

A. Five and four
B. Four and five
C. Three and four
D. Five and five

Explanation

To determine the number of B-O-B links and B-OH bonds in borax (Na2B4O7·10H2O), we need to analyze its structure.

### Step 1: Understand the Composition of Borax
Borax is a compound with the formula Na2B4O7·10H2O. This indicates that it contains boron (B), oxygen (O), sodium (Na), and water molecules (H2O).

### Step 2: Analyze the Structure of Borax
The structure of borax consists of boron atoms linked by oxygen atoms. In particular, we are interested in two types of bonds:
- B-O-B links (where two boron atoms are connected by an oxygen atom)
- B-OH bonds (where a boron atom is connected to a hydroxyl group, -OH)

### Step 3: Count the B-O-B Links
In the structure of borax, we can visualize the arrangement of boron and oxygen atoms. Each boron atom can form links with other boron atoms through oxygen. By examining the structure, we find:
- There are 5 B-O-B links present in borax.

### Step 4: Count the B-OH Bonds
Next, we need to identify the number of B-OH bonds. Each boron atom can also bond with a hydroxyl group. By analyzing the structure, we find:
- There are 4 B-OH bonds present in borax.

### Final Answer
Thus, the number of B-O-B links and B-OH bonds in borax are, respectively:
- **5 B-O-B links**
- **4 B-OH bonds**