The pair that contains no P-H bonds in each of the oxoacids is :

Options

A. `H_4P_2O_5 and H_3PO_3`
B. ` H_3PO_3and H_3PO_2`
C. ` H_3PO_4and H_4P_2O_6`
D. ` H_3PO_2 and H_4P_2O_5`

Answer

To solve the question regarding which pair of oxoacids contains no P-H bonds, we will analyze the structures of the given oxoacids and identify the presence or absence of P-H bonds.

### Step-by-Step Solution:

1. **Identify the Given Oxoacids**:
The oxoacids provided are:
- H3PO3 (Phosphorous acid)
- H4P2O5 (Diphosphoric acid)
- H3PO2 (Hypophosphorous acid)
- H3PO4 (Orthophosphoric acid)
- H4P2O6 (Diphosphoric acid)

2. **Draw the Structures**:
- **H3PO3**:
- Structure: P=O, 2 OH groups, and 1 H directly bonded to P.
- Contains P-H bond.
- **H4P2O5**:
- Structure: P-O-P linkage with 2 double-bonded O on each P and 2 OH groups.
- Contains no P-H bond.
- **H3PO2**:
- Structure: P=O, 1 OH group, and 2 H directly bonded to P.
- Contains P-H bonds.
- **H3PO4**:
- Structure: P=O, 3 OH groups.
- Contains no P-H bond.
- **H4P2O6**:
- Structure: P-O-P linkage with 2 double-bonded O on each P and 4 OH groups.
- Contains no P-H bond.

3. **Identify Pairs with No P-H Bonds**:
- From the analysis:
- H3PO3: Contains P-H bond.
- H4P2O5: No P-H bond.
- H3PO2: Contains P-H bonds.
- H3PO4: No P-H bond.
- H4P2O6: No P-H bond.
- The pairs that contain no P-H bonds are:
- H4P2O5 and H3PO4
- H4P2O6 and H3PO4

4. **Select the Correct Pair**:
- The pair that contains no P-H bonds is **H3PO4 and H4P2O6**.

### Final Answer:
The pair that contains no P-H bonds is **H3PO4 and H4P2O6**.