## Chemistry: The Molecular Science (5th Edition)

Chemical equation for the formation of this complex ion. $Ag^+(aq) + 2CN^-(aq) \lt -- \gt [Ag(CN)_2]^-(aq)$ Formation constant expression: $K_f = \frac{[[Ag(CN)_2]^-]}{[Ag^+][CN^-]^2}$
1. Identify the cation and the anion, and balance their coefficients: $[Ag(CN)_2]^-$ Cation: $1 Ag^+$ Anion: $2 CN^-$ Now, write the chemical equation: $Ag^+(aq) + 2CN^-(aq) \lt -- \gt [Ag(CN)_2]^-(aq)$ 2. To write the formation constant expression: $K_f = \frac{[Products]}{[Reactants]} = \frac{[[Ag(CN)_2]^-]}{[Ag^+][CN^-]^2}$