Which of the following statements is/are true if 1 mol of `H_(3)PO_(x)` is completely neutralized by 40g of NaOH?

Options

A. x = 2 and acid is monobasic
B. x = 3 and acid is dibasic
C. x = 4 and acid is tribasic
D. x = 2 and acid does not form acid salt

Explanation

To solve the question, we need to analyze the information given and determine the validity of the statements regarding the neutralization of 1 mole of \( H_3PO_x \) by 40g of NaOH.

### Step-by-Step Solution:

1. **Calculate Moles of NaOH:**
- The molar mass of NaOH is 40 g/mol.
- Given that we have 40 g of NaOH:
\[ \text{Moles of NaOH} = \frac{40 \, \text{g}}{40 \, \text{g/mol}} = 1 \, \text{mol} \]

**Hint:** Remember that the number of moles can be calculated using the formula:
\[ \text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}} \]

2. **Neutralization Reaction:**
- The neutralization reaction can be represented as:
\[ H_3PO_x + NaOH \rightarrow \text{Products} \]
- For neutralization, the equivalents of acid must equal the equivalents of base.

3. **Determine the Valency Factor (n):**
- The valency factor (n) for NaOH is 1 because it can donate one hydroxide ion (OH⁻).
- Since 1 mole of NaOH neutralizes 1 mole of \( H_3PO_x \), the valency factor for \( H_3PO_x \) must also be 1.

4. **Identify the Possible Forms of \( H_3PO_x \):**
- The formula \( H_3PO_x \) indicates that it is a phosphoric acid derivative.
- The possible values for \( x \) can be 2, 3, or 4:
- \( H_3PO_2 \) (phosphorous acid) - can release 1 H⁺
- \( H_3PO_3 \) (phosphoric acid) - can release 2 H⁺
- \( H_3PO_4 \) (phosphoric acid) - can release 3 H⁺
- Since \( H_3PO_x \) is neutralized by 1 mole of NaOH, it can only release 1 H⁺ ion, indicating \( x = 2 \).

5. **Conclusion on Acid Type:**
- Since \( H_3PO_x \) can only release one H⁺ ion, it is monobasic.
- Therefore, \( H_3PO_2 \) is the only valid form for \( H_3PO_x \) in this context.

6. **Determine the Nature of the Salt Formed:**
- When \( H_3PO_2 \) reacts with NaOH, it forms an acidic salt \( NaH_2PO_2 \) and water.
- Since it can only release 1 H⁺, it cannot form a normal salt.

### Final Statements:
Based on the analysis:
- The true statements regarding \( H_3PO_x \) are:
1. It is monobasic (can release only 1 H⁺).
2. It can form an acidic salt when reacting with NaOH.