Question

7. Explain why pure liquids and solids can be
ignored while writing the value of the equilibrium
constant.​

Answer 1

Answer:

For a pure substance (both solids and liquids),

Pure Substance = Numeber of moles / Volume

= Mass/Molecular Mass / Volume

= Mass / Volume x Molecular Mass

= Density / Molecular Mass

Now,The molecular mass and density (at a particular temperature) of a pure substance is always fixed and is accounted for in the equilibrium constant. Therefore, the values of pure substances are not mentioned in the equilibrium constant expression.

Answer 2

Explanation:

Molar concentration of a pure liquids or solids is constant. That's why pure solids and liquids can be ignored while writing the equilibrium constant expression.