Step 1
The reaction:
HCl (aq) => H+ + Cl-
[HCl] = [H+ ] = [Cl-] = 3.0x10^-4 M
This is a strong acid
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Step 2
pH is calculated as:
[tex]pH\text{ = -log \lbrack H+\rbrack}[/tex]Therefore, pH = - log (3.0x10^-4 M) = + 3.52
Answer: pH = +3.52