if 200mg of HCl is added to water to achieve a final volume of 1.00 L, what is the final pH?

Answer 1

200 mg HCl = ?? moles.
0.200 g/molar mass HCl = moles.
Since HCl is a strong acid (it ionizes 100%), that will be the (H3O^+) in 1.00 L, therefore, M is that amount.
Then pH = -log(H3O^+).