Pure solids and liquids in reaction quotients

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stester77s

Full Member
7+ Year Member
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Hello, it's known that "pure solids and liquids" are not included in equilibrium or reaction quotient expressions.

Take this expression:

2NO2(g)+H2O(l) <-> HNO2(aq)+HNO3(aq)

In this, H2O(l) is not taken into the equilibrium expression - correct?

However, removal of H2O will change the direction of equilibrium because it changes the concentration of HNO2 and HNO3. This question came from BR, and they say that it will not effect the concentration of NO2. Why does it change the concentrations of HNO2 and HNO3, but not NO2?

Thanks