Calculate the concentration of acetic acid (pka 54.76)and sodium acetate necessary to prepare a 0.2 m buffer solution at pH 5.0

See explanation below

Explanation:

To solve this problem, we need to use the Henderson - Hasselbach equation which is the following:

pH = pKa + log ([A⁻] / [HA])   (1)

Where:

[A⁻] = concentration of the acetate

[HA] = concentration of the acetic acid.

With the above expression, we can calculate the ratio of [A⁻] / [HA]. This concentration ratio will be used to calculate the individual concentrations. We know that a buffer is made as a mix of the acid and it's ion, in other words:

[HA] + [A⁻] = [Buffer]   (2)

So, with the concentration ratio, we can replace it here in (2) and then, we can calculate each concentration required.

First, let's use (1) to get the concentration ratio:

5 = 4.76 + log ([A⁻] / [HA])

5 - 4.76 = log ([A⁻] / [HA])

0.24 = log ([A⁻] / [HA])

[A⁻] / [HA] = 10⁰°²⁴

[A⁻] / [HA] = 1.7378

From this ratio, we can express either HA or A in function of the result. In this case, we will solve for A:

[A⁻] = 1.7378[HA]

With this expression, we can replace it in (2) to solve for [HA]:

[HA] + 1.7378[HA] = 0.2

2.7378[HA] = 0.2

Now all we have to do is replace this value in [A] to get the concentration:

[A⁻] = 1.7378 * 0.0731

chemistry sucks a**

explanation:

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >