Topic: Calculating the pH of an acidic salt (Read 5695 times)

student8607 · « **on:** March 03, 2009, 02:27:59 PM »

I'm fine when I'm given the concentration + the Ka value, but how would I solve for the pH of this:

0.25M NH₄Br

?

Borek · « **Reply #1 on:** March 03, 2009, 02:51:57 PM »

NH₄⁺ - what's that?

student8607 · « **Reply #2 on:** March 03, 2009, 03:04:59 PM »

Ammonium?

sjb · « **Reply #3 on:** March 03, 2009, 03:53:46 PM »

OK, so what's the Ka of the ammonium ion?

student8607 · « **Reply #4 on:** March 03, 2009, 04:16:00 PM »

5.6 x 10^-10
I got it now. (pH of 4.92)
The Ka is always given in the book so I assumed there was another way to do it since the Ka wasn't given.

Thanks.

AWK · « **Reply #5 on:** March 04, 2009, 12:56:15 AM »

K_a x K_b = K_w (always, so you can calculate it)

Borek · « **Reply #6 on:** March 04, 2009, 03:38:01 AM »

edit: deleted to not confuse anyone

AWK · « **Reply #7 on:** March 04, 2009, 05:01:30 AM »

pH is OK I got 4.91 using activities

Borek · « **Reply #8 on:** March 04, 2009, 05:20:34 AM »

Sorry, ignore my post, I have flipped everything 180 deg

Quote from: AWK on March 04, 2009, 05:01:30 AM

pH is OK I got 4.91 using activities

IS=0.25, have you used Davies equation, or something?

AWK · « **Reply #9 on:** March 09, 2009, 02:55:59 AM »

I used aq_solution recommended by IUPAC. It use Millero-Pitzer method for calculation of activity coefficients

Topic: Calculating the pH of an acidic salt (Read 5695 times)

student8607

Calculating the pH of an acidic salt

Borek

Re: Calculating the pH of an acidic salt

student8607

Re: Calculating the pH of an acidic salt

sjb

Re: Calculating the pH of an acidic salt

student8607

Re: Calculating the pH of an acidic salt

AWK

Re: Calculating the pH of an acidic salt

Borek

Re: Calculating the pH of an acidic salt

AWK

Re: Calculating the pH of an acidic salt

Borek

Re: Calculating the pH of an acidic salt

AWK

Re: Calculating the pH of an acidic salt

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