Question

For the following equation label the conjugate acid-base pairs.

HC2H3O2 + NH3 <===> NH4+ + C2H3O2-

2. The formation of products is strongly favored in this acid-base system: HX + B- <===> HB + X- a)

Identify the bases competing for protons.

b) Which is the weaker acid in the above equation? Explain.

c) Which base is the stronger? Explain.

d) How would the equilibrium be affected by the addition of the soluble salt, NaB?

e) Would the Keq for this reaction have a relatively large or small value? Explain.

4. Barium oxide reacts with water forming barium hydroxide.

a) Write the net ionic equation for this reaction.

b) What does this observation tell you about the relative strengths of the oxide and hydroxide ions as Bronsted bases?

5. This series of reactions proceeds predominantly to the right as written.

HC2H3O2 + NH3 <===> NH4 + + C2H3O2 -

HBr + H2O <===> H3O+ + Br -

NH4 + + OH- <===> NH3 + H2O

H3O+ + C2H3O2- <===> H2O + HC2H3O2

Arrange the bases NH3, H2O, OH- , C2H3O2 - and Br - in order of increasing basic strength. Under your ranking for the Bronsted bases, list the formulas of their conjugate acids.

6. Complete the following reactions, then indicate, using information in question 5, in which direction equilibrium is shifted.

HBr + C2H3O2- <===>

NH4+ + Br - <===>

Answer 1

For the following equation label the conjugate acid-base pairs.

HC2H3O2 + NH3 <===> NH4+ + C2H3O2-

HC2H3O2 - acid , C2H3O2- - conjugate base

NH3 - base , NH4+ - conjugate acid

conjugate acid / base pair = HC2H3O2 / C2H3O2-

conjugate acid / base pair = NH4+ / NH3

2. The formation of products is strongly favored in this acid-base system: HX + B- <===> HB + X-

a)

bases = B- , X-

b)

HB is weaker acid. , because it comes from strong base , B-

c)

strong base = B-

d)

equilibrium shifts to forward direction .

HX + B- <===> HB + X-

here if we add NaB , B- concentration increase , so reactants concentration increases, then the equilibrium shits to products side