[troy611]

While calculating the equilibrium constant for any reaction, why is the equilibrium concentration of a pure solid/liquid taken as one?

Thanx for any help....

[salleebrowne]

The equilibrium concentration of pure solids and liquids are taken to be ZERO not one. This happens because the concentrations of these cannot change. Go back and look up the definition of conentration and you should find why the concentrations of these cannot change.

[Borek]

The equilibrium concentration of pure solids and liquids are taken to be ZERO not one. This happens because the concentrations of these cannot change. Go back and look up the definition of conentration and you should find why the concentrations of these cannot change.

Concentration equal ZERO? Wow. Think what it will mean to equilibrium constant value.

Troy: please search forums, this problem was discussaed many times.

[salleebrowne]

OK - Yes, I was incorrect, I deserved a mole snack taken for that one.  I guess that I was thinking that since the concentrations of those pure solids and liquids do not change, we look right past them, but that certainly doesn't mean that they are zero in the expression. Yes - it would have a disatrous effect on the eq. constant. I'll be more careful with my responses in the future!