Why is enthalpy of mixing zero?

1 Answer
Bio
Nov 3, 2015

This is only true for ideal solutions.

Explanation:

For ideal gases, the particles do not interact with one another so there is no bond formed/broken.

For ideal solutions, the solvent-solvent and solute-solute intermolecular forces are approximately as strong as the solvent-solute interaction, and thus the net energy required is zero.

For non-ideal solutions, this is not true. For example, dissolving NaOH in a beaker of pure water is an exothermic process.

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