Question

For the reaction of hydrazine (N2H4) in water, Kb is 3.0 10-6.
H2NNH2(aq) + H2O(l) H2NNH3+(aq) + OH -(aq)

Calculate the concentrations of all species and the pH of a 2.2 M solution of hydrazine in water.


okay so i don't know how to do this problem because its dealing with Kb i only know how to do Ka what is the difference?

Answer 1

You do these the same way except with Ka you are dealing with the ionization of an acid and with Kb you are dealing with the base and the reaction with water.
Kb = (H2NNH3^+)(OH^-)/(H2NNH2)
Do an ICE chart and solve for (OH^-).
Post your work if you get confused along the way. My answer, without using the quadratic equation, is about 2.6 for the pOH.