Why Covalent Compounds are not soluble in water?

Covalent compounds are found in many items we use every day. Water, for example, is a covalent compound made up of two hydrogen atoms and one oxygen atom.

In addition to being found in food and drink, covalent compounds are also found in many household cleaning products.

For example, bleach is a covalent compound that contains chlorine atoms. Soap is another common cleaning product that contains covalent compounds; it is made of fatty acids that contain carbon, hydrogen, and oxygen atoms.

In short, covalent compounds are an important part of our lives, and we encounter them on a daily basis without even realizing it.

Even DNA, the molecule that contains our genetic information, is a covalent compound.

Before proceeding, let’s answer

Why Covalent Compounds Are Not Soluble In Water?

Covalent compounds are not soluble in water because they dissociate into molecules, not into ions.

Although water is a polar solvent, covalent compounds are nonpolar. This is because the sharing of electrons in a covalent bond creates a symmetrical distribution of charge, resulting in a molecule that is electrically neutral.

In contrast, water molecules are electrically polarized, with the oxygen atom carrying a partial negative charge and the hydrogen atoms carrying partial positive charges.

As a result, water molecules are attracted to other polar molecules and are able to form hydrogen bonds. This explains why covalent compounds are generally not soluble in water, as the nonpolar molecules are unable to form hydrogen bonds with the water molecules.

In this article, we’ll cover the following topics to cover complete knowledge:

  1. Solvent And Solute
  2. Significance Of Electronegativity In Water Solubility
  3. Like Dissolves Like In Covalent Compounds
  4. Charge Distribution In The Water Molecule
  5. Solubility Of Covalent Compounds In Water
  6. Organic And Water Solvent 
  7. Dipole Moment In Covalent Molecules
  8. Dissociation Of Ions Vs Molecules

Covalent compounds are different from ionic and metallic compounds because they do not have ions. This means that covalent compounds cannot dissolve in water. However, some can be dissolved in organic solvents like alcohols and ethers. 

solvent and solute

When a substance is dissolved in another substance, the resulting mixture is called a solution. The substance that is doing the dissolving is called the solvent, while the substance that is being dissolved is called the solute.

In most cases, the solvent is a liquid, although it can also be a gas or a solid. The solute, on the other hand, can be any type of substance, including another liquid, gas, or solid. Solutions can be either homogeneous or heterogeneous.

Common solvents include water, alcohol, and petroleum. The type of solvent you use will depend on the type of solute you are trying to dissolve. For example, water is a good solvent for salt, but it is not effective for oil.

Conversely, alcohol dissolves oil more readily than water does. In general, polar solvents are better at Dissolving polar solutes, while nonpolar solvents are better at Dissolving nonpolar solutes.

When choosing a solvent, it is important to consider the properties of both the solvent and the solute in order to find a compatible combination.

Significance of Electronegativity in Water Solubility

Water is considered to be a universal solvent, meaning that it can dissolve a wide variety of substances. This is due, in part, to water’s high electronegativity.

Electronegativity is a measure of the ability of an atom to attract electrons to itself. Atoms with a high electronegativity will tend to pull electrons away from other atoms, resulting in a molecule with a negative charge.

This can have a significant impact on the chemical properties of a compound.

This is due in part to the fact that water molecules are highly polar, meaning that they have regions of positive and negative charges. The electronegativity difference between the oxygen and hydrogen atoms creates this polarity, and it also enables water molecules to form strong bonds with other molecules.

These charges make water molecules attracted to charged or polar molecules, such as salt or sugar. The charges also allow water molecules to form hydrogen bonds with each other, giving water its unique properties.

Without electronegativity, water would be less effective at dissolving other substances and would not have the same remarkable abilities.

Like dissolves like in Covalent Compounds

The rule of “like dissolves like” is a simple way to remember which solvents are best for dissolving different substances. The rule states that a solvent will dissolve a substance if the two have similar properties.

For example, water is a good solvent for salt because both are polar molecules. This means that they have opposite charges at their ends, which allows the water molecules to surround and break up the salt crystals.

By contrast, oil is not a good solvent for salt because the molecules are both non-polar. This means that they do not have opposite charges, and thus the oil cannot break up the salt crystals.

In general, polar solvents dissolve polar substances and non-polar solvents dissolve non-polar substances. This rule can be helpful in choosing the right solvent for a particular job.

Charge distribution in the water molecule

The water molecule is made up of two hydrogen atoms and one oxygen atom. The distribution of charge within the molecule is uneven, with the oxygen atom carrying a slightly negative charge and the hydrogen atoms carrying a slight positive charge.

This uneven distribution of charge is what gives water its unique properties.

For example, it is the reason why water is able to form hydrogen bonds with other molecules. Hydrogen bonds are relatively weak, but they are important in stabilizing the structure of molecules.

Additionally, the uneven charge distribution within water molecules makes them highly polar, which means that they are attracted to other polar molecules.

This property of water explains why it is such an effective solvent; it can easily break apart other molecules and dissolve them in its own structure.

Solubility of Covalent Compounds in Water

When it comes to mixing different substances, water is usually a pretty good solvent. That’s because water molecules are polar, meaning that they have a slightly negative charge at one end and a slightly positive charge at the other. This allows water molecules to form weak bonds with other molecules, which allows them to dissolve a wide variety of substances.

However, there are some exceptions to this rule. Covalent compounds, which are held together by covalent bonds, are nonpolar and as a result, are insoluble in water. This means that they don’t dissolve and instead form a separate layer on the surface of the water.

Instead, it will remain in its original form. Covalent compounds are insoluble in water because they do not interact with polarized water molecules. Instead, they interact with each other, forming a nonpolar bond. As a result, they are unable to dissolve in water and must remain on the surface.

Organic and Water Solvent of Covalent Compounds

Covalent compounds are formed when atoms share electrons in order to achieve stability. The nature of the bond between the atoms determines the properties of the compound. For example, covalent compounds are generally insoluble in water because the water molecules are attracted to each other by hydrogen bonds.

In contrast, covalent compounds are soluble in organic solvents, such as oils and alcohols, because the solvent molecules are not attracted to each other. The solubility of a covalent compound in a given solvent depends on the nature of the bond between the atoms. If the bond is nonpolar, then the compound will be soluble in a nonpolar solvent. If the bond is polar, then the compound will be soluble in a polar solvent.

Dipole Moment in Covalent Molecules

A molecule’s dipole moment is a measure of its polarity. Dipole moments arise from the difference in electronegativity between two atoms in a bond. The higher the difference in electronegativities, the greater the dipole moment.

Polar molecules have dipole moments, while nonpolar molecules do not. The magnitude of a molecule’s dipole moment is dependent on the bond angle; the greater the bond angle, the greater the dipole moment.

Dipole moments are also affected by hybridization; sp-hybridized orbitals have a larger dipole moment than pure p-orbitals.

Finally, the presence of lone pairs on an atom also contributes to a molecule’s dipole moment. Lone pairs occupy more space than bonded pairs, leading to a larger dipole moment.

By understanding how dipole moments are affected by various factors, chemists can gain insights into the structure and reactivity of molecules.

Dissociation of ions vs molecules

Ions are atoms that have gained or lost electrons, giving them a net positive or negative charge. When an ionic compound is dissolved in water, the ions are surrounded by water molecules and are said to be “hydrated.”

The hydration of ions is a reversible process, meaning that the ions can re-associate with each other to form the original compound.

In order for this to happen, however, the hydration energy (the energy required to break the ionic bonds) must be overcome. The hydration energy is directly related to the strength of the ionic bond; the stronger the bond, the more energy required to break it.

Dissociation occurs when the hydration energy is greater than the bond energy, meaning that the ions will remain separated in the solution.

However, if the bond energy is greater than the hydration energy, then the ions will re-associate and precipitate out of the solution.

On the other hand,

Some covalent bonds do not have an ionic character and don’t form ions. but the dissociation of molecules can take place.

In general, covalent bonds are very stable and require a large amount of energy to break. However, there are some circumstances where dissociation can occur spontaneously. For example, when water molecules are heated to a high enough temperature, they will break apart into their constituent hydrogen and oxygen atoms.

Similarly, when certain types of molecules are exposed to light, they may dissociate into smaller fragments. While dissociation is usually an endothermic process (one that absorbs heat), in these cases it is exothermic (one that releases heat).

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