Net Ionic Equilibrium Constant

[Andrew Greenberg 2D]

I have currently been working through some of the exercises in the textbook when I came across a topic that I do not fully understand. Can someone explain the answer to this net ionic equilibrium reaction.
Question:Write the equilibrium constant for the reaction: 2AgNO3(aq)+2NaOH(aq)<>Ag2O(s)+2NaNO3(aq)+H2O(l)
Answer:K=1/[Ag]^2*[OH]^2

[Martha Tuna 1K]

Hi,

Page 401 of the textbook states "when a reaction involves fully dissociated ionic compounds in solution, the equilibrium constant should be written for the net ionic equation". Based on the text, I would assume that this is how you would solve the problem.

So in 2AgNO3(aq)+2NaOH(aq)<>Ag2O(s)+2NaNO3(aq)+H2O(l), we see that Ag2O is a solid and H2O is a liquid so they are not accounted for in the equilibrium constant.

Excluding those, we have the chemical equation 2AgNO3(aq)+2NaOH(aq)<>2NaNO3(aq)

Next, we find the net ionic equation by separating the ions so
2Ag + 2NO3 + 2Na + 2OH <> 2Na + 2NO3

Next, we remove the ions that are on both sides of the equation and get
2Ag + 2OH <> 0

Since we have nothing left on the products side, when we set up the equilibrium constant we would put 1 as the concentration for products because it technically has a coefficient of 0 and anything to the power of 0 is one. This would explain why the answer is K=1/[Ag]^2*[OH]^2.

Hope this helps!