How many grams of sodium acetate ( molar mass = 83.06 g/mol ) must be added to 1.00 Liter of a 0.200 M acetic acid solution to make a buffer with a pH of 5.00. Assume no volume change with addition of the solid. ( Ka of acetic acid = 1.8 x 10 -5 )

The mass of sodium acetate that must be added is 30.23 grams

Explanation:

To calculate the number of moles for given molarity, we use the equation:

Molarity of acetic acid solution = 0.200 M

Volume of solution = 1 L

Putting values in above equation, we get:

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

We are given:

= negative logarithm of acid dissociation constant of acetic acid = 4.74

pH = 5.00

Putting values in above equation, we get:

To calculate the mass of sodium acetate for given number of moles, we use the equation:

Molar mass of sodium acetate = 83.06 g/mol

Moles of sodium acetate = 0.364 moles

Putting values in above equation, we get:

Hence, the mass of sodium acetate that must be added is 30.23 grams

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