Step 1: Recall the formula for pH
The pH of a solution is determined by the formula:\[\text{pH} = -\log[\text{H}^+]\]where \( [\text{H}^+] \) represents the concentration of hydrogen ions in the solution.
Step 2: Use the concentration of HCl
Hydrochloric acid (HCl) is a strong acid and dissociates completely in water:\[\text{HCl} \rightarrow \text{H}^+ + \text{Cl}^-\]Consequently, the concentration of \( \text{H}^+ \) ions equals the concentration of HCl, which is \( 0.001 \, \text{M} \).\[[\text{H}^+] = 0.001 \, \text{M}\]
Step 3: Calculate the pH
Substitute the concentration of \( \text{H}^+ \) into the pH formula:\[\text{pH} = -\log(0.001) = 3\]
Answer:
The pH of the 0.001 M HCl solution is \( 3 \). Thus, option (1) is the correct answer.