contestada

You need to produce a buffer solution that has a pH of 5.39. You already have a solution that contains 10. mmol (millimoles) of acetic acid. How many millimoles of acetate (the conjugate base of acetic acid) will you need to add to this solution?

Respuesta :

Answer:

Milli moles of acetate = 43.65 mmol

Explanation:

The pH of a buffer solution is calculated using Henderson Hassalbalch's equation, which is:

[tex]pH=pKa+log\frac{[salt]}{[acid]}[/tex]

Where

[Salt] = concentration of salt (sodium acetate, the conjugate base)

[acid] = concentration of acid (acetic acid) = 10 mmol

pH = 5.39

For acetic acid

pKa =4.75

Putting values

[tex]5.39=4.75+log\frac{[acetate]}{[10mmol]}[/tex]

[tex]0.64=log\frac{[acetate]}{10}[/tex]

Taking antilog

[tex]4.365=\frac{[acetate]}{10}[/tex]

moles of acetate = 43.65 mmol