What is the sum of the oxidation state of phosphorus and number
of P-OH bonds in `H_3PO_4`?

Explanation

To solve the problem, we need to find two things: the oxidation state of phosphorus in H₃PO₄ and the number of P-OH bonds in the molecule. Let's break it down step by step.

### Step 1: Determine the number of P-OH bonds in H₃PO₄
1. **Identify the structure of H₃PO₄ (orthophosphoric acid)**:
- H₃PO₄ consists of one phosphorus atom (P), four oxygen atoms (O), and three hydrogen atoms (H).
- The structure can be visualized as one phosphorus atom bonded to four oxygen atoms, where three of these oxygen atoms are also bonded to hydrogen atoms (OH groups).

2. **Count the P-OH bonds**:
- In H₃PO₄, there are three OH groups.
- Therefore, the number of P-OH bonds is **3**.

### Step 2: Calculate the oxidation state of phosphorus in H₃PO₄
1. **Set up the oxidation state equation**:
- Let the oxidation state of phosphorus be \( X \).
- The oxidation states of hydrogen and oxygen are known: hydrogen is +1 and oxygen is -2.
- The overall charge of the molecule is neutral (0).

2. **Write the equation based on the contributions of each atom**:
- The contribution from hydrogen: \( 3 \times (+1) = +3 \)
- The contribution from oxygen: \( 4 \times (-2) = -8 \)
- The equation can be set up as:
\[ 3 + X - 8 = 0 \]

3. **Solve for \( X \)**:
- Rearranging the equation gives:
\[ X - 5 = 0 \implies X = +5 \]
- Therefore, the oxidation state of phosphorus in H₃PO₄ is **+5**.

### Step 3: Sum the oxidation state of phosphorus and the number of P-OH bonds
1. **Add the values obtained**:
- Oxidation state of phosphorus: +5
- Number of P-OH bonds: 3
- Sum = \( 5 + 3 = 8 \)

### Final Answer
The sum of the oxidation state of phosphorus and the number of P-OH bonds in H₃PO₄ is **8**.

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