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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Nathan001 on April 20, 2008, 10:17:08 AM

Title: activity coefficient,ph
Post by: Nathan001 on April 20, 2008, 10:17:08 AM

hi, please help me with these questions:

Calculate the activity coefficient of a 0.75M solution of NaCl using the Debye-Huckel limiting law.  A = 0.509

A freighter carrying drums of NH4OH is wrecked. In order to assess the effect of this upon the marine life, you need to ascertain the pH of the solution in the drums. The drums contain a 0.05M solution of the weak salt and only 0.2% of the molecules are dissociated. What is the pH?

NH4OH ===> NH4+ + OH

thank you so much!

Title: Re: activity coefficient,ph
Post by: AWK on April 21, 2008, 01:03:02 AM

Debye-Huckel limiting law is valid up to I at least not greater than 0,1.
You should use a more advanced equation