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Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: aemalcolm on September 03, 2008, 10:57:47 PM

Title: Working with buffers.... another question
Post by: aemalcolm on September 03, 2008, 10:57:47 PM

So we've moved onto buffers and I'm struggling again....
Any suggestions would be very helpful, for example
A buffer contains 0.01 mol of lactic acid (pKa = 3.86) and 0.05 mol of sodium lactate per liter
*Calculate pH of the buffer - which I was able to do using pH = pKa + log (A-/HA)
pH = 4.6 but here's where I struggle
*Calculate the change in pH when 5 mL of 0.5 M HCl is added to 1 L of the buffer....? Any suggestions?

Title: Re: Working with buffers.... another question
Post by: Yggdrasil on September 03, 2008, 11:17:20 PM

How do you think HCl will react with the solution?  Will it affect the amount of lactic acid?  Will it affect the amount of sodium lactate?