Pyrophosphorous acid, `H_(4)P_(2)O_(5)`

Options

A. contains Pin +5 oxidation state
B. is dibasic acid
C. is strongly reducing in nature
D. contains one P-0-P bond

Explanation

To solve the question regarding pyrophosphorous acid, \( H_4P_2O_5 \), we will analyze each statement provided in the question step by step.

### Step 1: Determine the Structure of Pyrophosphorous Acid
Pyrophosphorous acid has the formula \( H_4P_2O_5 \). The structure can be represented as:
- It consists of two phosphorus atoms connected by an oxygen atom (P-O-P).
- There is one double-bonded oxygen (O) to one of the phosphorus atoms.
- Additionally, there are two hydroxyl groups (OH) attached to the phosphorus atoms.

### Step 2: Calculate the Oxidation State of Phosphorus
To find the oxidation state of phosphorus in \( H_4P_2O_5 \):
1. Let the oxidation state of phosphorus be \( x \).
2. The total charge of the molecule is 0.
3. The contributions are:
- Hydrogen (H) has a +1 charge, and there are 4 hydrogens: \( 4 \times (+1) = +4 \)
- Oxygen (O) has a -2 charge, and there are 5 oxygens: \( 5 \times (-2) = -10 \)
4. Setting up the equation:
\[ 4 + 2x - 10 = 0 \]
\[ 2x - 6 = 0 \implies 2x = 6 \implies x = +3 \]
Thus, the oxidation state of phosphorus in pyrophosphorous acid is +3.

### Step 3: Analyze Each Statement
1. **Statement 1**: Contains P in +5 oxidation state.
- **Analysis**: This statement is incorrect; phosphorus is in the +3 oxidation state.

2. **Statement 2**: It is a di-basic acid.
- **Analysis**: Pyrophosphorous acid has 2 replaceable hydrogen ions (H), making it di-basic. This statement is correct.

3. **Statement 3**: It is strongly reducing in nature.
- **Analysis**: Pyrophosphorous acid can donate hydrogen ions, which can act as reducing agents. Therefore, this statement is correct.

4. **Statement 4**: Contains 1 P-O-P bond.
- **Analysis**: The structure indeed contains one P-O-P bond. This statement is correct.

### Conclusion
From the analysis:
- Statement 1 is incorrect.
- Statements 2, 3, and 4 are correct.

Thus, the correct options are 2, 3, and 4.

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