The extent of fragmentation for ionic compounds can be derived by comparing the molality expected if no dissociation with what is actually obtained from experiment. When 0.278 g of K3Fe(CN)6 (molar mass 329.25 g/mol) is dissolved in 100.0 g of water, the freezing point is found to be -0.070 °C. How many ions are present for each formula unit of K3Fe(CN)6 dissolved? (Kf for water is 1.86 K/m).
The answer is 5.
In water, the complex salt dissociates: K4Fe(CN)6 ==> 4K^+ + Fe(CN)6^-4
When K4Fe(CN)6 dissociates in water, there are 5 ions. Is this all I need to know for this problem, or these types of problems when asking for ions present? I'm confused. I'd appreciate any help. :-)