Tomas
Thank for your posting. That calculation in the picture are not mine. Are the one that I react when I make the comments that you said that your HCL conc is not 35. I did not practice chemistry since 1989 so i dont have in my mind the concentration of HCL and other acid that we have common in the bench. Those numbers are constant in our brain when we work as chemist. Now is back in my memory so when i saw the calculation that required Molarity and he put 35, I assume that the molarity of the HCL concentrated was 35 but my calculation did not give me the 4% that he was saying that the online calculator give him.
Hope this clarify the confusion. Your calculation really make feel good. Sound more clear.