Stepwise and Overall Formation Constants for Complex Ions

Stepwise and Overall Formation Constants for Complex Ions 

The formation of Ni(CN) (Table 9-2) is typical in that it occurs in steps as shown. Note that stepwise formation constants are symbolized by K, K2, and so forth. 

Aqueous solutions contain small concentrations of hydronium and hydroxide ions as a consequence of the dissociation reaction 

An equilibrium constant for this reaction can be formulated as shown in Equation 9-7  

The concentration of water in dilute aqueous solutions is enormous, however, when compared with the concentration of hydrogen and hydroxide ions. As a consequence, [H2OP in Equation 9-10 can be taken as constant, and we write 

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