posted by chamy .
Write the equation for the equilibrium that exists when nitrous acid and sodium acetate are placed in solution together (do not include spectator ions). Using published values for the Ka of nitrous acid and of acetic acid, determine the numerical value of the equilibrium constant for that equilibrium.
HNO2 + Ac^- ==> HAc + NO2^-
Keq = [(HAc)(NO2^-)/(HNO2)(Ac^-)]
If you multiply that expression by (H^+)/(H^+) you can see that it is KaHNO2/KaHAc.
Substitute Ka HNO2/Ka HAc and calculate Keq.