[bascid]

Hello.

I just want ask something. I just re-started to study chemistry after
many many years, and i forgot alot of things.

The one thing i wand ask is about pH.

Let's say we have 10mL of HCl (hydrocloric acid) at 30%

What happen if:

1) I dilute 10mL of HCl in 10mL of water (presumpted neutal).
1a) Will the concentration became 15% ?
1b) The pH of the HCl that is near 0 will became higher if i dilute in water? (presumpted neutral pH


2) I have 100mMol Acetic Acid which is pH 2,4 and i have 30% HCl which HCl is pH 0
2a) How much mL HCl30% i need to get the bioequivalent in acitity of 100mMol Acetic Acid?
2b) Will the HCl and Acetic Acid equalized in acidity, have the same biochemical properties? (for example on  cells)

[Borek]

You have to show your attempts at solving the problem to receive help, this is a forum policy.

[bascid]

Ok.

I know that 30% HCl in 1 litre is 300grams of HCl, so 0,3grams HCl in 1ml is 30%.

If i want dilute 30% HCl to 10% HCl, from 5ml 30% is 1,5 grams HCl

10% HCl in 5mL is 0,5 grams acid (1,5 / 3  == 10%*3)

5mL * 0,5gr / 1,5gr = 1,66 mL of 30% acid

then 5mL - 1,66mL = 3,34ml water i should add to have 5ml HCl of 10% instead of 5mL HCl 30%.


The other questions i ask help
 

[bascid]

The hard to understand is the correlation with pH and molecular mass.

HCl is about 36grams /mole while Acetic Acid is 60grams /mole
but HCl is near 0pH while Acetic Acid is 2,6 pH.

How can i bring HCl from 0pH to 2,6 pH with simply water dilution? (if possible).

[Borek]

I know that 30% HCl in 1 litre is 300grams of HCl

Depends on whether it is is w/w percentage or w/v percentage.

from 5ml 30% is 1,5 grams HCl

That's assuming 1 mL = 1 g, it is not. @30% definitely at least 1.1 g, you will need to consult density tables to check the exact value.

then 5mL - 1,66mL = 3,34ml water i should add to have 5ml HCl of 10% instead of 5mL HCl 30%.

That's assuming volumes are additive, they are not.

How is pH defined?

http://www.chembuddy.com/?left=pH-calculation&right=toc