quickest way to do this

[qshyrn]

What volume of pure water must be added to 10ml of 0.1 M HCl to change its pH to 3.0?
i hate these types of qstions cuz i always take so long to do them. i worl out the Hcl Conc at ph 3 then use the c1v1=c2v2 thing  .. is ther some shortcut?

[andy456]

Is the answer 990ml

[qshyrn]

yeah but what way did u do it?

[Potter]

Since it's a log scale everything works on bases of 10. If you have 10mL of a solution with pH of 1 and add 90mL , the pH will be 2 as it is diluted by a factor of 10. If it's diluted again to 1L the pH becomes 3.

[Studyinghard]

Is it me or 10ml of 0.1M HCL has a PH of 3

[appianway]

No, pH refers to concentration. 0.1 M HCl is always going to have a concentration of 0.1, thus the pH will always be 1.

[Potter]

Is it me or 10ml of 0.1M HCL has a PH of 3

Can't be. -log[H+]. -log[.1] = 1. pH is a measure of concentration, not how much there is.

[andy456]

Since it's a log scale everything works on bases of 10. If you have 10mL of a solution with pH of 1 and add 90mL , the pH will be 2 as it is diluted by a factor of 10. If it's diluted again to 1L the pH becomes 3.

This is how I did it.... all you need to do is -log[H+] in your calc and the rest you can do in your head.

[qshyrn]

Since it's a log scale everything works on bases of 10. If you have 10mL of a solution with pH of 1 and add 90mL , the pH will be 2 as it is diluted by a factor of 10. If it's diluted again to 1L the pH becomes 3.

nice didnt think of it like that

[superflya]

take it this way, if ur pH increases by 1, uve increased the volume tenfold. to increase pH by 2 u would have 10 x 10 x 10. that gives u 1000 ml but subtracting the initial 10ml gives u 990.