Question

How to calculate pH of `HCl`?

Answer 1

Well, by definition, `pH=-log_10[H_3O^+]`...we gets `pH=-1`

Explanation:

The conc. `HCl` we pour from a reagent bottle is typically `33%` `"w/w"`...and has a density of `1.16*g*mL^-1`...these are data I pulled from the web...

And so we can address the molar concentration with these data....

`"Concentration"="Moles of solute"/"Volume of solution..."`

And working from a `1*mL-=10^-3*L` volume we gots...

`((33%xx1.16*g)/(36.46*g*mol^-1))/(1.00xx10^-3*L)=10.5*mol*L^-1`

And, given that `pH=-log_10[H_3O^+]`...here `pH=-log_10(10.5)=-1.02`...

Normally, we would deal with much more dilute acid concentrations...and why should we add acid to water when we make these dilutions...