Question

What volumes of 2.00 M KOH and 0.200 M HCOOH are needed to make 0.500 L of buffer, pH = 3.50? pKa=3.74.

Answer 1

To create a buffer solution with a pH of 5.0 using acetic acid (CH3COOH) and sodium hydroxide (NaOH), we can use the Henderson-Hasselbalch equation to calculate the ratio of [A-]/[HA]. Once we have the ratio, we can determine the volumes of the acetic acid and NaOH solutions needed to make the buffer.

Step-by-step explanation:

To create a buffer solution with a pH of 5.0 using acetic acid (CH3COOH) and sodium hydroxide (NaOH), we can use the Henderson-Hasselbalch equation:

pH = pKa + log ([A-]/[HA])

Given that the pKa for acetic acid is 4.756 and we want a pH of 5.0, we can rearrange the equation to solve for the ratio of [A-]/[HA]. Once we have the ratio, we can use it to calculate the volumes of the 0.500 M acetic acid solution and 1 M NaOH solution needed to make the buffer.