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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: csinha on November 11, 2011, 08:47:05 PM

Title: Finding the equilibrium concentration of the conugate base
Post by: csinha on November 11, 2011, 08:47:05 PM

The question is: At 25 degrees celsius, the pH of an aqueous solution of benzoic acid, pKa = 4.202 is measured (at equilibrium) to be 3.61.

What is the equilibrium concentration of the conjugate base?

This is a multipart question but I listed the one I am having trouble with. Previous question asked to find concentration of H3O+; since pH is given it is just 10^-3.61 but would the concentration of the conjugate base not be equal to the concentration of H3O+?

Title: Re: Finding the equilibrium concentration of the conugate base
Post by: Borek on November 12, 2011, 05:26:56 AM

Quote from: csinha on November 11, 2011, 08:47:05 PM

would the concentration of the conjugate base not be equal to the concentration of H3O+?

It would in this case. Note that it doesn't have to be true for diluted solutions, when concentration of H⁺ from water autodissociation starts to play an important role.