[Glorzifen]

An example from my notes:

What is the pH of 0.1M NH4CH3COO dissolved in de-ionized water?
Ka (CH3COOH) = 1.8E-5
Kb (NH3) = 1.8E-5

NH4CH3COO(aq) -> NH4+(aq) + CH3COO-(aq)

CH3COO-(aq) + H2O(l) <-(Kb)-> CH3COOH(aq) + OH-(aq)
NH4+(aq) + H2O(l) <-(Ka)-> NH3(aq) + H3O+(aq)

Acidic or Alkaline Solution?
Kb = 5.5E-10 <-> Ka = 5.5E-10
pH =7 because equal magnitudes of Ka & Kb

Firstly, why can't you just see that Ka = Kb at the beginning? And where do the values of 5.5E-10 come from anyway? This is an example in my notes and I don't understand what is showing me or what's going on in it.

Any insight would be appreciated.

G

[Borek]

pKa + pKb = pKw