Question

How do i fill out an ICE chart when i am only given an initial concentration of one reactants and an equilibrium of another reaction?

inital 0.045 HNO2(aq)
Equilibrium 0.0043 H3O+(aq)
NO2(aq) - no information

my first thought was to sqaure root .0043 mol/l by 10 to find the change in H3O.

also should intial of H3O and NO2 be zero?

Answer 1

How do i find pH of HNO2 i just need a formula to follow cause i cant figure out the equation.

Answer 2

..........HNO2 ==> H^+ + NO2^-
I.........0.045M....0.....0
C.........-x........x.....x
E........0.045-x....x.....x

You know x = (H^+) = 0.0043M because the problem tells you this is the equilibrium concn of H3O^+; therefore,
pH = -log(H^+) = ?
BTW, the problem doesn't tell you the concn of NO2^-; however, you know it is the same as H^+. You also know (HNO2) at equilibrium; it is 0.045-x = ? Finally, the problem doesn't ask for Ka but you can calculate it from
Ka = (H^+)(NO2^-)/(HNO2)

Answer 3

isnt the equilibrium of HNO2 0.0407 because the equilibrium of H+ is 0.0043?
i am confused if no change occured in the reaction according to the chart...