Why can't some substances dissolve in water? Chemically?
Water is a polar molecule. If a solute dissolved in water is polar molecule, it will dissolve in water. If a solute dissolved in water is non-polar like oil it will not dissolve in water. b/c polar dissolves in polar
Shruti is correct: water is a polar molecule. Polar means that the molecule has a partially negatively charged end and a partially positively charged end. These partial charges will be attracted to partial charges in other polar substances - like, for example, the substance that it is trying to dissolve. This leads to water dissolving the polar substance because it disrupts the other non-covalent bonds which hold the molecules in the polar substance together. Substances without polar molecules don't have this problem - they don't have partial charges so water is not able to disrupt the non-covalent bonds holding them together. So water can't dissolve them. For what can and cannot be dissolved, there is a saying in chemistry: "Like dissolves like." If you have a substance made out of polar molecules, a polar solvent like water can dissolve it. If it is made out of non-polar molecules, then a non-polar solvent can dissolve it. Hope that is helpful.
yah @blues it should be like dissolves like.i wrote it in a wrong way
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