To make an acetate buffer at pH 4.76 starting with 500 mL of 0.1 M sodium acetate (pK acetic acid = 4.76),you could add
A)0)1 mol of NaOH.
B)0)2 mol of HCl.
C)0)025 mol of HCl.
D)0)1 mol of HCl.
E)You can't make a buffer by adding HCl or NaOH.

Question

Quizplus · Accepted Answer

To make an acetate buffer at pH 4.76, you need to adjust the ratio of acetate ions to acetic acid in the solution. Adding a strong acid like HCl will convert some of the acetate ions into acetic acid. The pKa of acetic acid is 4.76, which is the desired pH, so you want a 1:1 ratio of acetate to acetic acid. Since you're starting with 0.1 M sodium acetate in 500 mL (= 0.05 moles of acetate), adding 0.025 moles of HCl will partially neutralize the acetate, moving towards that 1:1 ratio, without completely neutralizing it, thus creating the desired buffer solution.

To Make an Acetate Buffer at PH 4