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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: madscientist on April 24, 2005, 10:54:58 PM

Title: calculating molarity from pH
Post by: madscientist on April 24, 2005, 10:54:58 PM

how do i get the molarity from pH?
the only quantative info i have to work with is: 75.0mL
(0.075 L) solution of "HCl", with a pH of 1.56.

my working is: [H+] = 10-pH = 10-1.56 = 2.75x10^-2M\L

But the question states: "From it's pH, calculate the molarity of HCl".

have I done this with my working or have I just gotten the hydrogen ion concentration ?

Any help or just a point in the right direction would be much appreciated.

Title: Re:calculating molarity from pH
Post by: AWK on April 25, 2005, 02:10:23 AM

For strong acids a concentrationacid and the concentration of H+ are the same.

Title: Re:calculating molarity from pH
Post by: Borek on April 25, 2005, 05:54:13 AM

For strong monoprotic acids, to be precise ;)

Title: Re:calculating molarity from pH
Post by: madscientist on April 25, 2005, 09:40:06 PM

 Thanks alot for the quick response!!

hopefully i can return tha favour one day