Question

Buffer Questions

1.) a.) How would you prepare .250 L of a 0.300 M phosphate buffer at pH=3 (H3PO4: pka1 = 2.12, pka2 = 7.21, pka = 12.32) using the appropriate weak acid and conjugate salt. b.) How would you prepare the assigned buffer (given in question #1a) if using combining the weak acid and 0.400 M NaOH? c.) How would you prepare the assigned buffer (given in question #1a) if using combining the weak acid and 0.400 M HCl?

2.) a.) What would be the pH of the buffer if 0.005 L of 1.10 M HCl was added to a .100 L  sample prepared buffer? After 0.01 L? 0.015 L? b.) Which of the volumes of added 1.10 M acid is the buffer capacity in acid exceeded?

3.) a.) What would be the pH of the buffer if 0.005 L of 1.10M NaOH was added to a .100 L  sample prepared buffer? After 0.01 L? 0.015 L? b.) Which of the volumes of added 1.10 M acid is the buffer capacity in base exceeded?

Sodium Phosphate Monobasic: MM = 137.99 g/mol

Sodium Phosphate Dibasic = 268.07 g/mol

Sodium Phosphate Tribasic = 380.14 g/mol

Phosphoric Acid: 98.0 g/mol

0.400 M HCl and NaOH

Answer 1

here I calculate the amount of NaH2PO4 and Na2HPO4 to prepare the phosphate buffer at pH =3, describe it is possible or not when added NaOH or HCl.

I answer the question no. 1, not 2 and 3 due to short time remaining to me.