If the dissolution of borax in water is non-spontaneous at room temperature, why does a very small amount still dissolve?

Question

I can't wrap my head around why the dissolution of borax still occurs (although very little) even though it's non-spontaneous at room temperature.

Answer 1

Even though the dissolution of borax in water is non-spontaneous at room temperature, a very small amount still dissolves because there is always some random thermal motion of the molecules, which leads to a small fraction of the solid particles colliding with the solvent molecules with enough energy to overcome the intermolecular forces that hold the solid together.

This process, known as "solvent-solute attraction," causes the solvent molecules to surround the solute particles and break apart the crystal lattice, allowing a small amount of borax to dissolve. The amount of borax that dissolves is usually very small because the process is not energetically favorable, and the majority of the solid remains undissolved.



In addition, the solubility of borax in water increases as the temperature increases, as this provides more energy for the particles to overcome the intermolecular forces, which is why more borax can be dissolved in hot water than in cold water.