The pH value of of `(M)/(1000)` HCl solution is

Options

A. `+5`
B. `-5`
C. `-7`
D. `+3`

Explanation

To find the pH value of a \((M)/(1000)\) HCl solution, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concentration**:
The concentration of HCl is given as \((M)/(1000)\). This means that the molarity of the HCl solution is \(10^{-3} M\) (or 0.001 M).

2. **Identify the Nature of HCl**:
HCl is a strong acid and it dissociates completely in water. Therefore, the concentration of hydrogen ions \([H^+]\) in the solution will be equal to the concentration of HCl.

3. **Calculate the Hydrogen Ion Concentration**:
Since HCl dissociates completely, the concentration of hydrogen ions \([H^+]\) is:
\[ [H^+] = 10^{-3} \, M \]

4. **Use the pH Formula**:
The pH of a solution is calculated using the formula:
\[ \text{pH} = -\log[H^+] \]
Substituting the value of \([H^+]\):
\[ \text{pH} = -\log(10^{-3}) \]

5. **Calculate the pH**:
Using the properties of logarithms:
\[ \text{pH} = -(-3) = 3 \]

6. **Conclusion**:
Therefore, the pH value of the \((M)/(1000)\) HCl solution is \(3\).

### Final Answer:
The pH value of the \((M)/(1000)\) HCl solution is **3**.