Question

In: Chemistry

Need to prepare an acetate buffer solution: 25.00 mL of 0.1 M acetic acid and 0.1...

Need to prepare an acetate buffer solution: 25.00 mL of 0.1 M acetic acid and 0.1 M sodium acetate. The stock acetic acid is 6.0 M. The instructions involve the preparation of a (10-fold) intermediate acetic acid solution. K_a = 1.75 x 10^-5 (pKa = 4.76). What are the values for the:

* volume of acetic acid

* grams of sodium acetate (since it's a solid)

* volume of DI water needed

* calculated pH

Thanks.

Expert Solution

Acetic Acid: for acetic acid, use the formula N₁V₁ = N₂V_2.

As the stock acetic acid is 6.0 M , N₁ = 6; V₁ = ?

as we need 25 ml of 0.1 M acetic acid , N₂ = 0.1 and V₂ = 25

Therefore, 6 * V₁ = 0.1 * 25, solving for V₁ we get V₁ = 0.42 ml

Thus for making 25 ml of 0.1M Acetic acid we will need 0.42 ml of 6.0M stock acetic acid and remaining i.e.,24.58ml Dl water.

pH calculation: Ka = 1.75 x 10^-5

[H⁺] = =

pH = -log(0.00000175) = 5.75

Sodium Acetate: Anhydrous sodium acetate has a molar mass of 82.03g.Thus by definition, 82.03g of sodium acetate in 1000ml will yield 1 M solution. Therefore, for a 0.1M solution, you need 8.203g of sodium acetate in 1000ml. Thus for 25 ml of 0.1M sodium acetate you will need 0.2 g (8.203/40) of sodium acetate in 25 ml(1000/40) of Dl water.

pH calculation: Sodium acetate is a weak base, a conjugate base of acetic acid, so:

Ka ×Kb =K_w = 10^-14. therefore kb = 10^-14/ (1.75 x 10^-5) = 5.7142857 x 10^-10

[OH^-] =

pOH = -log(0.00000755928) = 5.12

queen_honey_blossom answered 2 years ago

The pH of a solution made of 0.1 M acetic acid and 0.1 M potassium acetate...

The pH of a solution made of 0.1 M acetic acid and 0.1 M potassium acetate is (Ka = 1.8 x 10-5) to which 0.001 mol of KOH has been added: a) pH = 8.92 b) pH = 11.55 c) pH = 4.73 d) pH = 4.74

A 250.00 mL buffer solution is 0.250 M acetic acid (CH3COOH) and 0.100 M sodium acetate...

A 250.00 mL buffer solution is 0.250 M acetic acid (CH3COOH) and 0.100 M sodium acetate (NaCH3COO). The Ka of acetic acid is 1.8 • 10-5 at 25 o C. Calculate the pH of the resulting buffer solution when 10.00 mL of a 0.500 M aqueous HCl solution is added to this mixture.

You need to prepare an acetate buffer of pH 5.50 from a 0.899 M acetic acid...

You need to prepare an acetate buffer of pH 5.50 from a 0.899 M acetic acid solution and a 2.73 M KOH solution. If you have 775 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 5.50? The pKa of acetic acid is 4.76.

You need to prepare an acetate buffer of pH 5.54 from a 0.805 M acetic acid...

You need to prepare an acetate buffer of pH 5.54 from a 0.805 M acetic acid solution and a 2.64 M KOH solution. If you have 475 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 5.54? The pKa of acetic acid is 4.76.

You need to prepare an acetate buffer of pH 5.67 from a 0.841 M acetic acid...

You need to prepare an acetate buffer of pH 5.67 from a 0.841 M acetic acid solution and a 2.94 M KOH solution. If you have 675 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 5.67? The pKa of acetic acid is 4.76.

You need to prepare an acetate buffer of pH 5.83 from a 0.853 M acetic acid...

You need to prepare an acetate buffer of pH 5.83 from a 0.853 M acetic acid solution and a 2.61 M KOH solution. If you have 825 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 5.83? The pKa of acetic acid is 4.76.

You need to prepare an acetate buffer of pH 6.43 from a 0.743 M acetic acid...

You need to prepare an acetate buffer of pH 6.43 from a 0.743 M acetic acid solution and a 2.20 M KOH solution. If you have 830 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 6.43? The pKa of acetic acid is 4.76.

You need to prepare an acetate buffer of pH 6.22 from a 0.624 M acetic acid...

You need to prepare an acetate buffer of pH 6.22 from a 0.624 M acetic acid solution and a 2.84 M KOH solution. If you have 875 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a bufer of pH 6.22? The pKa of acetic acid is 4.76.

You need to prepare an acetate buffer of pH 6.22 from a 0.662 M acetic acid...

You need to prepare an acetate buffer of pH 6.22 from a 0.662 M acetic acid solution and a 2.71 M KOH solution. If you have 775 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 6.22? The pKa of acetic acid is 4.76. Answer in mL And please explain, Thanks!

You need to prepare an acetate buffer of pH 5.85 from a 0.649 M acetic acid...

You need to prepare an acetate buffer of pH 5.85 from a 0.649 M acetic acid solution and a 2.22 M KOH solution. If you have 925 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 5.85? The pKa of acetic acid is 4.76.