Question

What kind of compound would be least likely to dissolve in water?

Answer 1

Hint: It is not completely possible to determine whether a compound is soluble in a solvent or not without performing the practical. But we have some theories that are used to predict the relative solubilities. The one very famous axiom is – like dissolves like. Using this principle, we can easily tell which type of compound can be dissolved in a particular solvent.

Complete answer:
Water is a polar compound. It means that atoms present in water possess partial negative and positive charges on them. Due to the higher electronegativity of the oxygen atom, the electrons involved in bonding are displaced more towards the oxygen atom and thus it gains a partial negative charge. While the hydrogen atoms get partial positive charges. This is what makes the water a polar compound.
When a solute or compound dissolves, its atoms and molecules interact with the solvent molecules. The compound is said to be completely dissolved in a solvent only if some kind of bonding is present between the molecules of compound and solvent.
The extent to which a compound gets dissolved in a solvent is largely dependent on the chemical nature of both, whether they are ionic or non-ionic.
Based upon the principle of “like dissolves like”, the polar (or ionic) compounds are likely to dissolve in a polar solvent and non-polar compounds are likely to dissolve in non-polar solvents. The polar water molecules tend to form strong hydrogen bonds with polar compounds.
Thus, polar compounds are more likely to dissolve in water.

Note:
The highly polar nature of water molecules makes the water a universal solvent. It is because the polarization of water makes the different types of molecules attract toward it and thus water dissolves a larger number of chemicals than any other solvent.