posted by .

For an acetic acid-sodium acetate buffer to have a pH of 4.64, what molar ratio
of CH3COOH to Na+ CH3COO– is needed?

I know that the Ka value for acetic acid is 1.8e-5 and that I have to divide this value by the value of sodium acetate but I do not understand how you get the value for sodium acetate.

You want the molar ratio. The easy way to do that is to use the Henderson-Hasselbalch equation.
pH = pKa + log (base)/(acid)
4.64 = 4.74 + log(acetate)/(acetic acid)
Solve for the ratio of
acetate/acetic acid.

The other way to do it is
Ka = (H^+)(Ac^-)/(HAc)
Ka/(H^+) = (Ac^-)/(HAc)
1.8E-5/2.29E-5 = (Ac^-)/(HAc)

For the second way, where did the 2.29e-5 come from?

pH of 4.64. (H^+) = 2.29E-5

## Similar Questions

1. ### chemistry

You want to make an acetic acid/acetate buffer, pH 3.8, with a volume of 250 mL, and a final concentration of ([AcOH] + [AcO-]) = 0.1 M. You may only use acetic acid and sodium acetate (no strong acid or base). How many mL of glacial …
2. ### Science

Describe the procedure for preparing 250mL of buffer solution with a pH of 5.00 from acetic acid (CH3COOH) and sodium acetate. How many grams of acid do you have to mix with 3.6 grams of sodium acetate?
3. ### AP Chemistry

We're doing a lab in my class and we're supposed to make a buffer at a certain pH. I have decided to make a buffer with a pH of 5.0 using glacial acetic acid (pure CH3COOH) and sodium acetate. I found that the ratio of acid to base …
4. ### College Chemistry

If 10 mL of 1M NaOH are added to one liter of a buffer that is 0.3 M acetic acid and 0.2 M sodium acetate (Na+CH3COO-), how much does the pH change?
5. ### school

What is the pH of 0.1 M formic acid solution?
6. ### Chemistry

You want to prepare a pH=4.50 buffer using sodium acetate and glacial acetic acid. You have on hand 300 mL of 0.100 M sodium acetate. How many grams of glacial (water free) acetic acid should you add to prepare the buffer?
7. ### chemistry

Calculate the volume of 1.00 M acetic acid solution and mass of sodium acetate needed to make 250 mL of a 0.450 M acetic acid/acetate buffer solution with a pH of 4.00. (The pKa is 4.74 for acetic acid).
8. ### Chemistry

Calculate the volume of 1.00 M acetic acid solution and mass of sodium acetate needed to make 250 mL of a 0.450 M acetic acid/acetate buffer solution with a pH of 4.00. (The pKa is 4.74 for acetic acid) *Please explain it in detail, …
9. ### Chemistry

A solution of acetic acid, 1.0 mol L–1 CH3COOH, contains sodium acetate, NaCH3COO. The percent ionization of the above solution is 0.25%. The Ka for acetic acid is 1.8 x 10–5. Which of the following is the concentration of NaCH3COO …
10. ### CHEMISTY

How would you prepare 30 mL of acetic acid/acetate buffer solution of pH = 5.06?

More Similar Questions