Which of the following mixtures are buffers at equilibrium S

Which of the following mixtures are buffers at equilibrium? Select all that apply (there are multiple correct answers) Select one or more: a. 10 mL 1.0 Macetic acid+0.01 mL 1.0 M sodium acetate trihydrate b. 10 mL 1.0 MNH3+5 mL 1.0 M nitric acid C.5 mL of 1.0 MNH3+6 mL of 1.0 MNH CI d. 10 mL 1.0 MNH3+10 mL 1.0 M nitric acid e.10 mL 1.0 Macetic acid+10 mL 1.0 M sodium hydroxide f. 10 mL of 1.0 Msodium acetate trihydrate g. 10 mL of 1.0 Macetic acid 10 mL of 1.0 M sodium acetate trihydrate O h. 10 mL 1.0 Macetic acid+ 10 mL 0.5 Msodium hydroxide

Solution

Buffer is a mixture of weak acid and its salt or a mixture of a weak base and its salt

a) 10 mL of 1.0 M acetic acid + 0.01 mL of 1.0 M sodium acetate trihydrate is Buffer mixture

( acetic acid is weak acid and sodium acetate is its salt)

b) NH3 + HNO3 ---> NH4NO3

10 mL x 1.0 mol / 1000 mL => 0.01 mol NH3, 5 mL x 1.0 mol / 1000 mL => 0.005 mol HNO3

0.01 mol NH3 + 0.005 mol HNO3 ---> 0.005 mol NH4NO3 + unreacted 0.005 mol ( 0.01 - 0.005) NH3

so it is also Buffer mixture ( mixture of weak base NH3 and its salt NH4NO3)

c) it is also Buffer mixture ( mixture of weak base NH3 and its salt NH4Cl

d) It is not a buffer mixture

0.01 mol NH3 + 0.01 mol HNO3 ---> 0.01 mol NH4NO3 ( only salt presents absence of weak base)

e) It is not a buffer mixture

0.01 mol acetic acid + 0.01 NaOH ----> 0.01 mol sodium acetate ( only salt presents absence of weak acid)

f) It is not a buffer mixture ( only salt presents absence of weak acid)

g) It is a buffer mixture ( mixture of weak acid , acetic acid , and its salt sodium acetate)

h) 0.01 mol CH3COOH + 0.005 mol NaOH ---> 0.005 mol NaOOCCH3 + 0.005 mol CH3COOH (unreacted)

So it is also a buffer mixture ( mixture of weak acid , acetic acid , and its salt sodium acetate)