Chemistry - equation problem

1. Sep 18, 2007

JPC

1. The problem statement, all variables and given/known data

1) ok , first we have a solution of :
MnO2, C6H5COO- , OH-

we add Hydrochloric acid, the following reactions happen :
OH- + H3O+ = H2O
C6H5COO- + H3O+ = C6H5COOH + H2O

ok , now we are told that if we put in more Hydrochloric acid than needed, CO2 gas escapes, a question asks me for the equations of the reactions that produce this CO2

I am just told these Acid/Base couples :
HCO3- / CO3-2
CO2, H2O / HCO3-

2) No, with the same solution, with Hydrochloric acid being introduced in about the right proportions, we add a solution of (2Na+ +SO3-2)
Here, another question asks me for the equation of the reaction between MnO2 and SO2,H20

Here i am just told these Red/Ox couples :
MnO2 / Mn+2
SO3-2 / SO2, H2O

The Reaction environment is acid

2. Relevant equations

3. The attempt at a solution

1)
the semi equations :
HCO3- = CO3-2 + H+
CO2 + H2O = HCO3- + H+

C6H5COOH + H3O(+) = C6H5 + CO3-2 + 3H+ + H (cannot be H alone so * 2) :
2C6H5COOH + 2H3O(+) = 2C6H5 + 2CO3-2 + 6H+ + H2

then
CO3-2 + H+ = HCO3-
then
HCO3- + H+ = H2O + CO2

(here, im really not sure of my equations,and the paper doesnt even tell me that H2 gas escapes)

2) The semi equations :

MnO2 + 4H+ 2e- = Mn+2 + 2H2O

SO3-2 + 2H+ = SO2 + H2O (no e- in the reactions !!, how can it be an Ox/red reaction then ?)

Last edited: Sep 18, 2007