`2P overset(-H_(2)O) to Q overset(-[O])toR`
If P is parent phosphoric acid then according to given information the correct statement is/are:

Options

A. Q is pyro form and R is hypo form of givenn present oxy acid P
B. Number of H-atoms present in each given oxy acid is equal to its besicity
C. In P, Q, R oxy acids, oxidation state of central atom remains same.
D. All given oxy acids have `p pi- dpi` bond(s) in their structure

Explanation

To solve the question regarding the transformation of phosphoric acid (P) into pyrophosphoric acid (Q) and then into hypophosphoric acid (R), we will analyze the information step by step.

### Step 1: Identify the Parent Compound (P)
- **Given**: P is phosphoric acid (H₃PO₄).
- **Structure of P**: Phosphoric acid has the structure:
\[ \text{P} \quad (H_3PO_4) \quad \text{with the structure:} \quad \text{O} \quad \text{||} \quad \text{P} \quad \text{--} \quad \text{OH} \quad \text{--} \quad \text{OH} \quad \text{--} \quad \text{OH} \]

### Step 2: Transformation to Q (Pyrophosphoric Acid)
- **Process**: 2P → Q (removal of H₂O)
- **Result**: When two molecules of phosphoric acid are heated and a water molecule is removed, they form pyrophosphoric acid (Q).
- **Structure of Q**: The structure of pyrophosphoric acid (H₄P₂O₇) is:
\[ \text{Q} \quad (H_4P_2O_7) \quad \text{with the structure:} \quad \text{O} \quad \text{||} \quad \text{P} \quad \text{--} \quad \text{O} \quad \text{--} \quad \text{P} \quad \text{--} \quad \text{OH} \quad \text{--} \quad \text{OH} \]

### Step 3: Transformation to R (Hypophosphoric Acid)
- **Process**: Q → R (removal of O)
- **Result**: Removing one oxygen from pyrophosphoric acid results in hypophosphoric acid (R).
- **Structure of R**: The structure of hypophosphoric acid (H₄P₂O₆) is:
\[ \text{R} \quad (H_4P_2O_6) \quad \text{with the structure:} \quad \text{O} \quad \text{||} \quad \text{P} \quad \text{--} \quad \text{OH} \quad \text{--} \quad \text{P} \quad \text{--} \quad \text{OH} \quad \text{--} \quad \text{OH} \]

### Step 4: Analyze the Statements
1. **Statement 1**: Q is pyrophosphoric acid.
- **True**: As derived, Q is indeed pyrophosphoric acid.

2. **Statement 2**: R is hypophosphoric acid.
- **True**: As derived, R is indeed hypophosphoric acid.

3. **Statement 3**: The number of hydrogen atoms present in each oxyacid is equal to its basicity.
- **True**: The basicity of an acid is defined by the number of ionizable hydrogen ions (H⁺) it can release. In this case, the number of hydrogen atoms attached to oxygen (OH groups) corresponds to the basicity of each acid.

4. **Statement 4**: The oxidation state of the central atom remains the same in P, Q, and R.
- **False**: The oxidation state of phosphorus in phosphoric acid (P) is +5, in pyrophosphoric acid (Q) it remains +5, but in hypophosphoric acid (R), it is +4.

5. **Statement 5**: All given oxyacids have p-pi d-pi bonds in their structure.
- **True**: The presence of p-pi d-pi bonding can be observed in the bonding of phosphorus with oxygen in these oxyacids.

### Conclusion
The correct statements according to the transformations and properties of the acids are:
- **Correct Statements**: 1, 2, 3, and 5.

### Final Answer
The correct statements are 1, 2, 3, and 5.