Answer
$pH = 0.117$
Work Step by Step
1. Find the number of $HCl$ moles.
molar mass $(HCl)$: 1.01 + 35.45 = 36.46g/mol
$n(moles) = \frac{mass(g)}{molarmass(g/mol)}$
$n(moles) = \frac{18.4}{36.46} = 0.505$
2. Now, calculate the concentration of $HCl$:
$Concentration(M) = \frac{n(moles)}{Volume(L)}$
$C(M) = \frac{0.505}{0.662} = 0.763M$
3. HCl is a strong acid, therefore:
$[HCl] = [H^+] = 0.763M$
4. Calculate the pH:
$pH = -log[H^+] = -log(0.763) = 0.117$
