Question

What is the balanced equilibrium equation for a saturated solution of sodium hydrogen carbonate? Discuss the effect on this equilibrium of the addition of more water.

Answer 1

Saturation is an equilibrium property, which we may represent by the following equation:

Normally:

But the term [NaHCO3(s)] is meaningless; you cannot speak of the concentration of a solid; so it is removed from the equation:

So if solid sodium carbonate is present, this equilibrium operates, sodium carbonate is saturated. 

If we add extra water the precipitate would dissolve.