Reactions That Run To Completion
There are some reactions that are considered to run to completion. They do not set up an equilibrium but run until one of the reactants runs out. They basically fall into 3 basic categories.
 
1. Formation of a gas that is allowed to escape.

      Sugar -------> CO2 + H2O (not reversible)
 

2. Formation of a precipitate

      2 Tl+ + 2 Cl- -----> 2 TlCl (ppt)

The ppt is a solid that makes the equation heterogenous and essentially eliminates the TlCl from the Keq equation.
 

3. Formation of a slightly ionized product.

     NaCl(s) + KBr(s) --H2O--> Na+(aq) + Cl-(aq) + K+(aq) + Br-(aq)

Remove water and you would get a mixture of four products not just two. You would get NaCl, NaBr, KBr,& KCl
 

           Go to Introduction to Equilibrium Review Worksheet