Which of the following solutions has the lowest pH value ?

Options

A. 0 . 1 Molar NaCl solution
B. 0 .01 Molar `NaHCO_(3)` solution
C. 0 . 00 1 Molar `Na_(2)CO_(3)` solution
D. 0.01 Molar `NaOH` solution

Explanation

To determine which of the given solutions has the lowest pH value, we need to analyze each solution based on its acidic or basic nature. Here's a step-by-step breakdown of the solution:

### Step 1: Understand pH Values
- pH is a measure of how acidic or basic a solution is. A pH value of 7 is neutral, values less than 7 are acidic, and values greater than 7 are basic.

### Step 2: Analyze Each Solution
1. **0.1 M NaCl Solution**:
- NaCl is a salt formed from a strong acid (HCl) and a strong base (NaOH).
- When dissolved in water, it does not affect the pH significantly and remains neutral (pH ≈ 7).

2. **0.01 M NaHCO3 Solution**:
- NaHCO3 (sodium bicarbonate) is a weak base.
- When dissolved in water, it produces NaOH (strong base) and H2CO3 (weak acid).
- The resulting solution is basic (pH > 7).

3. **0.001 M Na2CO3 Solution**:
- Na2CO3 (sodium carbonate) is also a weak base.
- It produces NaOH (strong base) and H2CO3 (weak acid) when dissolved in water.
- This solution is also basic (pH > 7).

4. **0.1 M NaOH Solution**:
- NaOH is a strong base.
- When dissolved in water, it significantly increases the pH, making it highly basic (pH >> 7).

### Step 3: Compare the pH Values
- From the analysis:
- 0.1 M NaCl solution is neutral (pH ≈ 7).
- 0.01 M NaHCO3 solution is basic (pH > 7).
- 0.001 M Na2CO3 solution is basic (pH > 7).
- 0.1 M NaOH solution is highly basic (pH >> 7).

### Conclusion
- Among all the solutions, the **0.1 M NaCl solution** has the lowest pH value, which is neutral (approximately 7).

### Final Answer
- The solution with the lowest pH value is **0.1 M NaCl solution** (Option A).

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