Ever wondered why all the sand in water bodies or the sand on the shore near the sea doesn’t make the water muddy? The water remains clear as day, even though you can scoop buckets of sand from beneath the water body. The reason is that sand is insoluble in water which makes us wonder, why does sand not dissolve in water?
Sand does not dissolve in water due to the crystalline lattice of the silicate present in the sand. How the lattice prevents it from dissolving in water is still something you need to understand.
Why is sand insoluble in water?
When you try to dissolve salt or sugar in water, they don’t pose much of a problem. No matter how small you grind the sugar or salt, it is still solid and contains millions of molecules, closely packed together.
As you try to dissolve the substance in water, water molecules pull apart the solid molecules and surround them from all sides. However, this process certainly does not mean the sugar is not sugar anymore; the sugar molecules are still sugar molecules. They have been separated from each other at the molecular level, and therefore, we can’t see them.
The sand grains, on the other hand, are made of silicon dioxide which has a crystalline lattice structure. Even though you might stir to the best of your abilities, you can’t dissolve the sand in water as water cannot pull apart the molecules of sand due to the crystalline lattice.
There might be cases where the sand grains are made up of other materials, like salt. Therefore, when you try to dissolve such a kind of sand into water some of it will dissolve owing to the soluble substances in the sand like the salt. However, most of the grains will still accumulate at the bottom.
You can watch this video to get a better understanding:
Can I dissolve sand in something else?
Merely because sand is insoluble in water does not mean it is insoluble in every liquid. You can try a solution of sugar and ethanol or rubbing alcohol, add some water to it, and then dissolve the sand.
Can sand be dissolved in vinegar?
Unfortunately no; sand can not be dissolved in vinegar either. If you pour sand into a bottle of vinegar all you will see is some foaming and bubbles. But, the sand won’t dissolve in the vinegar.
The reason is that vinegar is a fairly weak acid, and therefore, it cannot pull apart the molecules of sand that are held together by strong intermolecular forces.
What makes salt or sugar so easily dissolvable in water?
As mentioned, it is the structure of the individual molecules that determine whether the substance is soluble in water or not. Sugar and salt have a structure that allows water molecules to pull them apart; the intermolecular forces between the molecules of sugar and salt are weak and therefore, easily breakable.
So, now you know why sand is insoluble in water and why salt and sugar are soluble; all of it depends on the molecular structure!