Which one is not an acid salt?

Options

A. `NaH_(2)PO_(4)`
B. `NaH_(2)PO_(2)`
C. `NaH_(2)PO_(3)`
D. All of the above are acid salts

Explanation

To determine which of the given options is not an acid salt, we need to understand what an acid salt is. An acid salt is a type of salt that, when dissolved in water, releases replaceable hydrogen ions (H⁺) and results in an acidic solution.

Let's analyze each option step by step:

### Step 1: Identify the options
The options given are:
1. NaH₂PO₄
2. NaH₂PO₂
3. NaH₂PO₃

### Step 2: Analyze NaH₂PO₄
- **Formation**: NaH₂PO₄ is formed from the reaction of H₃PO₄ (phosphoric acid) with NaOH (sodium hydroxide).
- **Replaceable H⁺ ions**: This compound has two replaceable hydrogen ions (H⁺) because it is derived from a triprotic acid (H₃PO₄).
- **Conclusion**: Since it can release H⁺ ions, NaH₂PO₄ is an acidic salt.

### Step 3: Analyze NaH₂PO₂
- **Formation**: NaH₂PO₂ is formed from the reaction of H₃PO₂ (phosphorous acid) with NaOH.
- **Replaceable H⁺ ions**: This compound has only one replaceable hydrogen ion because it is derived from a monoprotic acid (H₃PO₂).
- **Conclusion**: Since it does not have any replaceable H⁺ ions, NaH₂PO₂ is not an acidic salt; it is a neutral salt.

### Step 4: Analyze NaH₂PO₃
- **Formation**: NaH₂PO₃ is formed from the reaction of H₃PO₃ (phosphorous acid) with NaOH.
- **Replaceable H⁺ ions**: This compound has one replaceable hydrogen ion because it is derived from a dibasic acid (H₃PO₃).
- **Conclusion**: Since it can release H⁺ ions, NaH₂PO₃ is an acidic salt.

### Final Conclusion
Among the options provided, NaH₂PO₂ is the only compound that is not an acid salt.

### Answer
**NaH₂PO₂ is not an acid salt.**

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