Answer
Ka=4.46*10^-4
Work Step by Step
HNO2+H2O=NO2^- + H3O^+
Write the dissociation equation
-log[H^+]=1.83
[H^+]=1.47*10^-2
use the pH to solve for Hydrogen ion concentration (which is also the hydronium ion concentration.
Reaction: HNO2, NO2^-, H30^+
Initial: .50M, 0M, 0M
Change:-1.47*10^-2, +1.47*10^-2, +1.47*10^-2
Equilibrium: .485, 1.47*10^-2, 1.47*10^-2
Create a RICE chart to find equilibrium amounts
Ka= (1.47*10^-2)(1.47*10^-2)/.485
Plug equilibrium values into the equation Ka=[H^+][A^-]/[HA]
