Do Polar and nonpolar molecules dissolve in water?
Water can dissolve in polar or nonpolar substances if we speak about that, so you have to understand and read all articles to get your answer. Hence, the answer is that water is a polar substance, so it can easily mix with polar substances, but it is weak in combining with a nonpolar sense.
This topic is vital to understand how liquid solvent is mixed with solute and form a liquid solution.
Do all solvents dissolve all solute?
Not all solvents cannot be mixed with all solutes. It is divided into two parts, polar, also known as ionic, and nonpolar.
Now you need to understand the thumb, which is “like dissolve like.” This principle is straightforward, and you know that all polar substances or ionic substances can mix with polar substances, and nonpolar substances can mix with nonpolar substances.
Polar molecules cannot combine with polar, and nonpolar cannot mix with polar molecules.
For example, water is a polar substance, so it will mix with a polar substance such as NaCl and others that are polar. Water cannot mix with oil because it is nonpolar.
Petrol is nonpolar so the oil can integrate, but it cannot mix with water. Like dissolve is a straightforward method to find which molecule can combine.
Classes of the molecule:
There are two main classes of molecules. Some molecules are polar, and some are nonpolar. All about polar and nonpolar molecules are given below:
Firstly you have to be clear that it is a covalent bond. Polar molecules are those in which the number of electrons is not equally divided. Here is the dipole formation, where the molecule contains a slight positive charge, and the other side will be a bit negative charge.
This situation happens when there is a difference in the electronegativity value in the atom. We use a table to check the electronegativity of any molecule then we can estimate whether this molecule will form a polar bond or not.
Now I am telling you to value it to understand whether the molecule will form a polar bond or not. If the electronegativity value is between 0.5 and 2.0, the molecule will be polar.
The second point is that if the electronegativity is more than 2.0, the molecule will be ionic. In simple words, you can understand that ionic compounds are highly polar molecules.
Let’s take examples of polar molecules, which are given below:
- Water, the formula of water, is H20
- Ammonia, the formula of ammonia, is NH3
- Sulphur dioxide the formula of sulphur dioxide is SO2
- Hydrogen sulphide the formula of hydrogen sulphide is H2S
- Ethanol, the formula of ethanol, is C2H6O.
If the molecules share an equal number of electrons, it will be called nonpolar molecules if the number of electrons is equally divided so that there will be no charge difference. In other words, in nonpolar molecules, electrons are divided equally.
You can understand this nature of molecules if it contains the same number of electronegativity, so there will be no charge difference, and electrons will divide equally.
In general terms, you can understand nonpolar by if the electronegativity value is less than 0.5, the bond formation will be nonpolar. One thing important to note is that the nonpolar bond will only form with identical atoms.
- Examples of nonpolar molecules include:
- In the periodic table, the noble gases such as He, Ne, Ar, Kr, Xe (they are not molecules if we talk technically because they are atoms).
- Many diatomic molecules in the periodic table are H2, N2, O2, Cl2 (they are pure nonpolar molecules).
- Carbon dioxide the formula of carbon dioxide is CO2.
- Benzene the formula of benzene is C6H6
- Carbon tetrachloride the formula of carbon tetrachloride is CCl4
- Methane, the formula of methane, is CH4
- Ethylene, the formula of ethylene, is C2H4
- Hydrocarbon liquids are also nonpolar such as gasoline and toluene.
- Many organic compounds are also nonpolar.
Why do polar substances dissolve in water?
Like water, the polar substance also has a partially positive and partially negative charge. There will be charges between partial charges.
So that polar molecules easily mix with water. Polar molecules have charge differences to attract each other to form the molecule, as we know that polar molecules have a positive and negative charge.
These charges are made possible for NaCl to get drawn. Nonpolar cannot mix with water because it has no attraction with the water molecule.
One thing about polar molecules is that polar molecules contain –OH group (functional group). Then it will be the formation of a bond known as a hydrogen bond.
Why is polarity important?
The polarity of a molecule is fundamental because it defines the hydrophobic or hydrophilic molecule.
Hydrophilic vs. hydrophobic
First of all, we learn about Hydro, the word hydro means water. The characteristics of water molecules are defined by studying hydrophobic and hydrophilic. The meaning of phobic originates from phobia. The purpose of phobia is fear.
So we can define hydrophobic and hydrophilic in simple words; hydrophilic molecules are those molecules that can easily mix with water, which means they love water. On the other hand, hydrophobic molecules are those molecules that hate water, which means they cannot mix with water.
In other words, we can explain hydrophilic and hydrophobic molecules. Hydrophilic molecules will attract water, while hydrophobic molecules do not attract water molecules.
Water is polar, so it can only mix with polar substances. Like the dissolve-like principle, polar substances can mix with polar substances while nonpolar substances can mix with nonpolar substances.
For example, water is a polar substance to mix with ammonia. The formula of ammonia is NH3. It can combine with ammonia because it is also polar, while water cannot mix with a nonpolar substance such as oil.
It means water cannot mix with oil because water is polar in nature and oil is nonpolar. Oil can mix with petrol because both are nonpolar.
In simple words, polar can mix with polar, and nonpolar can mix with nonpolar.