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 problem, we need to analyze the neutralization reaction between the acid \( H_3PO_x \) and sodium hydroxide (NaOH). Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Reaction
The neutralization reaction can be represented as:
\[ H_3PO_x + NaOH \rightarrow Na_3PO_x + H_2O \]
We need to determine how many moles of NaOH are required to completely neutralize 1 mole of \( H_3PO_x \).

### Step 2: Calculate Moles of NaOH
We are given that 40 grams of NaOH is used. To find the number of moles of NaOH, we use the formula:
\[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \]
The molar mass of NaOH is calculated as follows:
- Sodium (Na) = 23 g/mol
- Oxygen (O) = 16 g/mol
- Hydrogen (H) = 1 g/mol

Thus, the molar mass of NaOH:
\[ \text{Molar mass of NaOH} = 23 + 16 + 1 = 40 \text{ g/mol} \]
Now, substituting the values:
\[ \text{Number of moles of NaOH} = \frac{40 \text{ g}}{40 \text{ g/mol}} = 1 \text{ mol} \]

### Step 3: Determine the Stoichiometry of the Reaction
From the balanced reaction, we can see that:
\[ 1 \text{ mole of } H_3PO_x \text{ reacts with } 3 \text{ moles of NaOH} \]
This means that \( H_3PO_x \) is a triprotic acid (can donate 3 protons) if it were to react with 3 moles of NaOH. However, since we only have 1 mole of NaOH reacting, we can conclude that only one of the hydrogen ions is ionizable.

### Step 4: Determine the Value of \( x \)
Since only one hydrogen ion is ionizable, we can infer that:
\[ H_3PO_x \text{ has } x = 2 \]
This leads us to the conclusion that the compound is \( H_3PO_2 \) (phosphorous acid), which is a monoprotic acid.

### Conclusion
Based on the analysis, the correct statement is that \( x = 2 \), and \( H_3PO_2 \) is a monobasic acid.

### Final Answer
The correct option is that \( x = 2 \) and it is a monobasic acid.

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