An aqueous solution of 1M NaCl and 1M HCl is

Options

A. not a buffer but pH `lt 7 `
B. not a buffer but pH ` gt 7`
C. a buffer with pH ` lt 7 `
D. a buffer with `pH gt 7`

Explanation

To determine the nature of the solution formed by mixing 1M NaCl and 1M HCl, we can analyze the components involved and their properties.

### Step-by-Step Solution:

1. **Identify the Components**:
- We have two components in the solution: Sodium Chloride (NaCl) and Hydrochloric Acid (HCl).
- NaCl is a salt formed from a strong acid (HCl) and a strong base (NaOH).
- HCl is a strong acid that completely dissociates in water.

2. **Dissociation of NaCl**:
- When NaCl is dissolved in water, it dissociates into Na⁺ and Cl⁻ ions:
\[ \text{NaCl} \rightarrow \text{Na}^+ + \text{Cl}^- \]

3. **Dissociation of HCl**:
- HCl also dissociates completely in water:
\[ \text{HCl} \rightarrow \text{H}^+ + \text{Cl}^- \]

4. **Total Ion Concentration**:
- From the 1M NaCl, we get 1M Na⁺ and 1M Cl⁻.
- From the 1M HCl, we get 1M H⁺ and 1M Cl⁻.
- The total concentration of Cl⁻ ions in the solution will be 2M (1M from NaCl and 1M from HCl).

5. **pH of the Solution**:
- Since HCl is a strong acid, it will dominate the pH of the solution.
- The concentration of H⁺ ions from HCl is 1M, which means the pH can be calculated as:
\[ \text{pH} = -\log[H^+] = -\log(1) = 0 \]
- This indicates that the solution is acidic.

6. **Buffer Capacity**:
- A buffer solution is typically formed from a weak acid and its conjugate base or a weak base and its conjugate acid.
- Since both NaCl and HCl are derived from strong acid and strong base, this solution cannot act as a buffer.
- The presence of a strong acid (HCl) means that the solution will not resist changes in pH effectively.

### Conclusion:
The solution of 1M NaCl and 1M HCl is acidic (pH < 7) and does not act as a buffer.

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