Assertion: There is a very little difference in acidic strengths of `H_(3)PO_(4),H_(3)PO_(3)` and `H_(3)PO_(2)`.
reason: Number of unprotonated oxygen (=O) responsible for increase of acidic strength due to inductive effective remains the same.

Options

A. If both (A) and (R) are true and (R) is the correct explanation of (A)
B. if both (A) and (R) are true but (R) is not correct explanation of (A)
C. If (A) is true but (R) is false
D. If (A) is false but (R) is false

Explanation

To solve the question regarding the assertion and reason about the acidic strengths of \( H_3PO_4 \), \( H_3PO_3 \), and \( H_3PO_2 \), we can break it down into a step-by-step analysis.

### Step 1: Understanding the Assertion
The assertion states that there is very little difference in the acidic strengths of \( H_3PO_4 \), \( H_3PO_3 \), and \( H_3PO_2 \).

### Step 2: Analyzing the Structures
- **\( H_3PO_4 \)** (Phosphoric acid) has the structure where phosphorus is bonded to four oxygen atoms, three of which are in hydroxyl groups (\(-OH\)) and one is a double-bonded oxygen (\(=O\)).
- **\( H_3PO_3 \)** (Phosphorous acid) has a similar structure but contains one less hydroxyl group, resulting in two hydroxyl groups and one double-bonded oxygen.
- **\( H_3PO_2 \)** (Hypophosphorous acid) has only one hydroxyl group and two double-bonded oxygens.

### Step 3: Basicity and Deprotonation
- The basicity of \( H_3PO_4 \) is 3, meaning it can release three protons.
- The basicity of \( H_3PO_3 \) is 2.
- The basicity of \( H_3PO_2 \) is 1.
- The number of deprotonated oxygens (unprotonated) is 3 for \( H_3PO_4 \), 2 for \( H_3PO_3 \), and 1 for \( H_3PO_2 \).

### Step 4: Evaluating the Reason
The reason states that the number of unprotonated oxygens responsible for increasing acidic strength due to inductive effects remains the same. This is important because:
- The presence of unprotonated oxygens can stabilize the negative charge that results from deprotonation, thus enhancing acidity.
- However, the difference in the number of unprotonated oxygens is not significant enough to cause a large difference in acidic strength among these three acids.

### Step 5: Conclusion
Both the assertion and the reason are correct. The assertion correctly states that there is little difference in acidic strength, and the reason correctly explains that the number of unprotonated oxygens contributes to this observation.

### Final Answer
The correct answer is that both the assertion and reason are correct, and the reason is a correct explanation of the assertion.

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