What kind of compounds can water dissolve

At the molecular level, salt dissolves in water due to electrical charges and due to the fact that both water and salt compounds are polar, with positive and negative charges on opposite sides in the molecule. The bonds in salt compounds are called ionic because they both have an electrical charge—the chloride ion is negatively charged and the sodium ion is positively charged. Likewise, a water molecule is ionic in nature, but the bond is called covalent, with two hydrogen atoms both situating themselves with their positive charge on one side of the oxygen atom, which has a negative charge.

When salt is mixed with water, the salt dissolves because the covalent bonds of water are stronger than the ionic bonds in the salt molecules. The positively-charged side of the water molecules are attracted to the negatively-charged chloride ions and the negatively-charged side of the water molecules are attracted to the positively-charged sodium ions. Essentially, a tug-of-war ensues with the water molecules winning the match. Water molecules pull the sodium and chloride ions apart, breaking the ionic bond that held them together.

After the salt compounds are pulled apart, the sodium and chloride atoms are surrounded by water molecules, as this diagram shows. Once this happens, the salt is dissolved, resulting in a homogeneous solution. Looking at water, you might think that it's the most simple thing around. Pure water is practically colorless, odorless, and tasteless. But it's not at all simple and plain and it is vital for all life on Earth.

Search for:. Learning Objective Explain why some molecules do not dissolve in water. Key Points Water dissociates salts by separating the cations and anions and forming new interactions between the water and ions.

Water dissolves many biomolecules, because they are polar and therefore hydrophilic. Examples Sugar, sodium chloride, and hydrophilic proteins are all substances that dissolve in water. Oils, fats, and certain organic solvents do not dissolve in water because they are hydrophobic. Substances that dissolve in water to yield ions are called electrolytes. Nonelectrolytes are substances that do not produce ions when dissolved in water. Solubility rules allow prediction of what products will be insoluble in water.

This page was constructed from content via the following contributor s and edited topically or extensively by the LibreTexts development team to meet platform style, presentation, and quality:. Austin State University with contributing authors. Learning Objectives Define and give examples of electrolytes. Water molecules in front of and behind the ions are not shown.

Solubility Rules Some combinations of aqueous reactants result in the formation of a solid precipitate as a product. They will precipitate only if rather concentrated solutions are used. All phosphates are insoluble, so Sr 3 PO 4 2 is insoluble. Summary Substances that dissolve in water to yield ions are called electrolytes. Skip to main content. Search Search. Water Science School. Water Science Activity Center Opinion surveys, questionnaires, and interactive learning Activity center.

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