Question

Determine the mass of sodium acetate necessary to produce 100 ml of an acetate buffer

Answer 1

Explanation:

Ethanoic acid is a weak acid and dissociates:

C

H

3

C

O

O

H

⇌

C

H

3

C

O

O

−

+

H

+

For which

K

a

=

[

C

H

3

C

O

O

−

]

[

H

+

]

[

C

H

3

C

O

O

H

]

=

1.8

×

10

−

5

Please remember that these are equilibrium concentrations .

p

K

a

=

−

log

K

a

=

−

log

[

1.8

×

10

−

5

]

=

4.74

n

=

c

×

v

∴

n

C

H

3

C

O

O

H

=

0.20

×

200.0

1000

=

0.04