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A buffer is prepared by adding 20.0 g of sodium acetate to 480 ml of a 0.160 m acetic acid solution. determine the ph of the buffer. the ka of acetic acid is 1.8 x 10-5

User Trumank
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Hello!

The chemical reaction for the dissociation of Acetic Acid is the following:

CH₃COOH + H₂O ⇄ CH₃COO⁻ + H₃O⁺

To solve the problem we are going to use the Henderson-Hasselbach Equation, as follows, but first we need to know the pKa:


pKa=-log(Ka)=-log( 1,8*10^(-5) )=4,74


pH=pKa + log( ([CH_3COO^(-) ])/([CH_3COOH]) )


pH=4,74+log( ((20 g CH_3COONa )/(0,480 L)* (1 mol CH_3COONa)/(82,03 g CH_3COONa) )/(0,160 M) )=5,24

So, the pH of this solution is 5,24

Have a nice day!
User Rukmal Dias
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