Which of the following explains why water is a good solvent for polar and ionic compounds?

Choose 1

(Choice A)

Water is a hydrophobic molecule.

(Choice B)

Water is an ionic compound.

(Choice C)

Water is a non-covalent molecule.

(Choice D)

Water is a polar molecule.

The answer is D. Water is a good solvent for polar and ionic compounds because Water is a polar molecule!

When we say that a molecule is polar, it just means that although they have both positive and negative charges, the positive and negative forces are not equal. Water molecules are composed of:

Hence the name H2O (hydrogen 2 and oxygen 1). The oxygen atom is among the most electrostatic atoms. This means that it has the ability to pull electrons to itself stronger than most other atoms, this electronegativity allows oxygen to form covalent bonds with the hydrogen atoms. Knowing this, we can conclude that option C is false.

When something is hydrophobic, it simply means that it will not mix with water and repels it. Since it does not make sense for water to repel itself, we can conclude that option A is also false.

Although it is often argued that water has ionic properties, it is not an ionic compound. It is instead a Polar molecule, therefore, option C is false.

Hydrogen atoms have a positive charge, while Oxygen atoms are negative. They are polar because the distribution of these charges are not even. This distribution allows the molecules to pull on both the positive and negative atoms within other molecules.

Water molecules are also smaller than many others, which means that a single body of water contains a vast number of molecules in comparison to other liquids. When water molecules pull on the positive and negative ends of other molecules, they apply force to the atoms within the other molecules. This force is multiplied by the number of water molecules present and is often enough to out-weigh the forces that hold molecules together. This happens for both the water and other molecules. This causes them to break apart into their atomic components. These components then form new molecules. This is the process of how a solvent and a solute combine into a solution and explains why water changes when we use it to dissolve something.

This is all thanks to the polarity of water. The reason water is a good solvent is that the uneven positive and negative forces (polar forces) allow it to break apart other molecules.

For more information on solvents and solutes go to: link

Hi there!

Electronegativity is the concept of how likely an atom is to attract the shared molecules in one of these bonds to itself. We know the molecule water is made up of two hydrogens and one oxygen. The electronegativity of hydrogen is 2.2, and oxygen 3.4. An ionic bond needs at least a difference in electronegativity of 1.6. As the difference is less than that, we can say that water is a covalent molecule. This then wipes out choice B, because it is not ionic, and C, as we have seen it is actually covalent.

Now, we can see the difference in electronegativity between oxygen and hydrogen is still 1.2. This means that while it is not at the point for there to be an ionic bond, there is still a difference in attraction, where the electrons will tend to favor the oxygen more and 'hang around it' more. As electrons are negatively charged, this means that the oxygen will gain a slightly negative charge. This then makes the molecule polar, because it now has a charge within the molecule. This means we have our answer, choice D.

In terms of hydrophobic molecules - they tend to be ones without a charge. (If you're interested in this kind of stuff, I'd search hydrophobic up, and possibly also look into hydrogen bonds).

Hope this helps! Feel free to ask me any other questions you have about this specific problem.