Hydrochloric acid is an inorganic chemical compound. It is colorless in appearance and forms aqueous-based solutions used in laboratories. It gives out a pungent smell. Many students may have a query about whether HCl is polar or not. In this article, I will make you understand the concept of polarity and will cover its properties and applications.
So, is HCl polar or Nonpolar? HCl (hydrochloric acid) is a polar molecule because the chlorine is more electronegative than hydrogen due to which it attracts the bonded electron pair slightly nearer to it and gains a partial negative charge and hydrogen gains partial positive charge. The dipole moment of HCl turns out to be 1.03 D.
Hydrochloric acid is colorless in color and has a pungent odor. In the form of an aqueous solution, it is widely used in chemistry laboratories in high school and universities.
This compound exists in the liquid state and also forms fumes if present in high concentrations.
The molecular mass of hydrochloric acid is 36.46 g/mol. It can be calculated as
Mol mass of HCl = 1* (Mol mass of H) + 1 * 35.5(Mol mass of Cl) = 36.46 g/mol.
If we talk about the chemical composition of hydrochloric acid, it consists of 1 hydrogen molecule and 1 chlorine molecule.
Being a diatomic molecule, the geometrical shape formed is linear.
It is a very frequently used chemical compound. It was discovered in 800 AD by alchemist Jabir ibn Hayyan.
The electronegativity of hydrogen is 2.2 D and that of chlorine is 3.16 D.
Being higher electronegative, the chlorine atom attracts the bonded electron pair with more influence and gains a partial negative charge.
As a result hydrogen atom gains a partial positive charge and becomes a positive pole.
Why is HCl a Polar Molecule?
Hydrochloric acid consists of 2 atoms ie; hydrogen and chlorine. Both of them have an appreciable difference in their electronegativity.
Chlorine is more electronegative than hydrogen. And it must be clear that higher electronegative atom attracts the electron bond pair slightly more towards it.
As a result, the chlorine atom gets a relatively negative charge and it becomes the negative pole whereas the hydrogen gains a relatively positive charge and becomes a positive pole.
In this way, two poles (positive and negative) poles are generated across a molecule. And the molecule turns out to be polar.
The dipole moment of a polar molecule is always non zero. Similarly, the dipole moment of HCl is 1.03 D. And the direction of the dipole is towards the chlorine atom (H->Cl).
Dipole Momentis a vector quantity. It has a magnitude as well as direction.
Polar Molecules and Nonpolar Molecules
The characteristics of the molecules depend upon the various parameters. The chemical bonding among the atoms of a molecule and the properties of atoms forming it make the characteristics of a molecule.
The existence of covalent bonding across a molecule and the electronegativity of atoms can determine whether a molecule is polar or not.
Let us check the differences between both types of molecules
The polar molecules have unequal distribution of charges across it whereas the nonpolar molecules have an overall equal distribution of charges among its atoms.
The dipole moment is the measure of the polarity of a molecule. The dipole of a nonpolar molecule is always 0 D whereas the polar molecules have the value of dipole moment equals to non zero.
The geometrical shape of the polar molecule is seen distorted or bent due to which the distribution of charge is non-uniform.
On the other hand, nonpolar molecules are shaped symmetrically.
The examples of polar molecules are BrF3, OF2. You can check out the reason for the polarity of BrF3.
And the examples of Nonpolar molecules are Cl2, No2+. You can check out the reason for the non-polarity of NO2+.
The important parameters that determine the polarity of a molecule
Electronegativity: the term electronegativity decides what charge will be dispersed on an atom. Two atoms that differ in their electronegativity forms a polar chemical bond.
This is because higher electronegative atom attracts the charge across its side and becomes a negative pole and in return, another atom becomes a positive pole.
Greater the difference between the electronegativity of both atoms more is the polarity of that molecule.
Dipole Moment: The dipole is the term that is used to measure of the polarity of the molecule. Greater the value of the dipole of a molecule more is its polarity.
The dipole moment is defined as the product of the charge and the distance between the centers of positive and negative charges.
The dipole moment value of the HCl molecule is 1.03 D originating towards the direction of the chlorine atom.
Whereas the molecules like Chlorine gas (Cl2) and oxygen gas (O2) are nonpolar and exhibit 0 D dipole moment.
Geometrical shape: the shape of a molecule is also a key point to check if a molecule is polar or not. It is generally observed that the symmetrical structure molecule is nonpolar in nature.
These molecules have equal charge distribution on their atoms and become overall nonpolar molecules.
The polar molecules have distorted shape due to which the charge distribution on its atoms is unequal. The atoms share an unequal proportion of charge.
Below is the image of 3D geometrical structure of the HCl molecule.
Properties of HCl
- Hydrochloric acid exists in a liquid state with a pungent smell at standard conditions of temperature and pressure.
- The physical properties of this acid vary with the concentration of HCl acid in aqueous solution.
- Hydrochloric acid is a mixture of HCl acid and water with a concentration of 20.2% HCl at a temperature of 108.6 °C.
- It is considered as a strong acid.
- It is a monoprotic compound that means it can release one proton.
- It is also secreted in the intensive for the digestive system with a ph value of 1 to 2.
Uses of HCl
- It is used for the production of Organic Compounds.
- It is widely used to remove the stains from the metals.
- This acid is also used for the purpose of purification of the table salt.
- It is also widely used for the production of oil.
Hydrochloric acid being diatomic molecule have two atoms (hydrogen and chlorine). Chlorine being higher electronegative attracts the bonded electron pair slightly towards its side and gains a partial negative charge.
Hydrogen becomes the positive pole and chlorine becomes a negative pole. Due to the difference between electronegativity, the bond between H and Cl becomes polar.
Due to these reasons, the HCl molecule is polar.
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