Question

What is the concentration of `1*mL` of conc, `HCl` added to `199*mL` of water?

Answer 1

Well add `1*mL` of conc. hydrochloric to approx. `200*mL` of distilled water....

Explanation:

The order of addition is important, given that [if you spit in acid it spits back.](https://socratic.org/questions/how-should-you-dilute-concentrated-acid) And thus acid is added to water, and NEVER the reverse.

Conc. `HCl` is approx. `10*mol*L^-1` with respect to `HCl(aq)`. But by definition, `"concentration"="moles of solute"/"volume of solution"`...

...and so we gots....

`(1xx10^-3*Lxx10*mol*L^-1)/(200*mLxx10^-3*L*mL^-1)=0.05*mol*L^-1`...

The actual concentration of the acid you make would need to be quantitatively measured by titration with standardized base.