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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: desperate4ananswer on June 22, 2007, 04:17:24 AM

Title: Buffer preparation
Post by: desperate4ananswer on June 22, 2007, 04:17:24 AM

I get it when I'm asked to prepare a buffer made up of weak acid and a strong base but I don't know how to prepare one with a weak base and a strong acid.

The question is:-
Prepare 1L of pH9 buffer from ethanolamine (liquid, specific gravity 1.1, Molecular weight=61) and HCl solution (1.0mol/L).

Somebody could help me with this, it would be greatly appreciated.

Thank you.

Title: Re: Buffer preparation
Post by: AWK on June 22, 2007, 04:30:36 AM

You need Kb of ethanolaamine

Title: Re: Buffer preparation
Post by: Borek on June 22, 2007, 05:18:36 AM

It goes exactly the same way as when using weak acid, you just use pOH and pK_b. See pH of buffer (http://www.chembuddy.com/?left=pH-calculation&right=pH-buffers-henderson-hasselbalch).