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Mikian · 09-20-2006, 02:57 AM

Can anyone please help me on this topic: what is the effect of pH on extent of ionization ? I've the following equation, but how does it really work?
pH= pKa + log [A]salt
______
[HA]acid

pH= pKa+log [b]base
_______
[BH+]salt

Thanks.

panne · 09-20-2006, 06:07 PM

Acids:
pH > pKa --- Completely ionized
Bases:
pKb > pH --- Completely ionized

Weak Acids

pH = pKa + log (ionized/unionized)

%ionized= 10pH-pKa/(1+ 10pH-pKa) *100

Weak bases
pH = pKb+ log (unionized/ionized)

%ionized= 10pKb-pH/(1+10pKb-pH) *100

Mikian · 09-21-2006, 02:26 AM

Is that the standard formula to find %ionized ? If not, what is number 10 in %ionized ? Thanks.

panne · 09-21-2006, 08:07 PM

10 to the power of (pH-pKa)
Understand

09-20-2006, 02:57 AM	#1 (permalink)
Mikian Eager! Join Date: Sep 2006 Posts: 54	Effect of pH on ionization Can anyone please help me on this topic: what is the effect of pH on extent of ionization ? I've the following equation, but how does it really work? pH= pKa + log [A]salt ______ [HA]acid pH= pKa+log [b]base _______ [BH+]salt Thanks.

09-20-2006, 06:07 PM	#2 (permalink)
panne Trying to make mom and pop proud Join Date: May 2005 Posts: 11	Effect of pH on Ionization Acids: pH > pKa --- Completely ionized Bases: pKb > pH --- Completely ionized Weak Acids pH = pKa + log (ionized/unionized) %ionized= 10pH-pKa/(1+ 10pH-pKa) 100 Weak bases pH = pKb+ log (unionized/ionized) %ionized= 10pKb-pH/(1+10pKb-pH) 100

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09-21-2006, 02:26 AM	#3 (permalink)
Mikian Eager! Join Date: Sep 2006 Posts: 54	Is that the standard formula to find %ionized ? If not, what is number 10 in %ionized ? Thanks.

09-21-2006, 08:07 PM	#4 (permalink)
panne Trying to make mom and pop proud Join Date: May 2005 Posts: 11	10 to the power of (pH-pKa) Understand

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