Is HCl Polar or Nonpolar?

Is HCl Polar or Nonpolar?

Hydrogen Chloride (HCl) is a polar molecule due to the higher electronegativity difference between Hydrogen (2.2) and Chlorine (3.16) atoms. Chlorine has higher E.N than hydrogen so that Cl atom attracts electron from H atom causes the formation of a partial positive charge on chlorine and partial negative charge on hydrogen, as a result, the HCl molecule has a net dipole moment.

Detailed Explanation: Why is HCl a Polar Molecule?

HCl, whose chemical name is hydrogen chloride, is one of the frequently used acids. The aqueous solution of hydrogen chloride is known as hydrochloric acid which we use most of the time in the laboratory.

is HCl polar or nonpolar?

Before entering deep inside HCl polarity first, have some basic ideas about what polar and nonpolar molecules are:

Polar Molecules

Polar molecules are defined as the presence of polar bond within the molecule or have irregular geometry (not symmetrical structure) so that the net dipole moment of molecule can’t be zero as the center of gravity of negative charge and positive charge is separated by a small distance. In the absence of an electric field, the moment of polar molecules in dielectric substances are randomly oriented but as soon as the electric field is applied, it tends to align along the direction of the field.

These molecules are used to show little ionic as well as covalent characteristics i.e. they are soluble in water (H2O), a good conductor of heat and electricity, have a strong electrostatic force of attraction, and many mores ionic characteristic despite having covalent bonds i.e. mutual sharing of electrons.

Example of Polar molecules: Water (H2O), Nitrogen Dioxide (NO2), Ammonia (NH3) etc.

Nonpolar Molecules

Nonpolar molecules are considered as pure covalent bonded molecules which are formed by mutual sharing of electrons and have a net dipole moment zero. In nonpolar molecules, there is no occurrence of partial positive and negative charge on the atoms because of the same electronegativity different between the atoms (Diatomic molecules like H2, O2, N2, etc) or molecule has regular geometry (symmetrical molecules like CH4, CCl4, CO2, etc) so bond polarities are canceled by each other.

When Nonpolar molecules are placed in an electric field, the center of gravity of the positive charge moves in direction of the field, and the center of the gravity of the negative charge in opposite direction. This separation between positive and negative charges continue until the applied external force and internal force are balanced.

Example of Nonpolar molecules: All homonuclear diatomic molecules (H2, N2, O2, F2, Cl2, Br2, and I2), most of the heteronuclear diatomic, Carbon tetrachloride (CCl4), Carbon Dioxide (CO2) etc.

Hydrogen chloride (HCl) Polar or Nonpolar (On the basis of characteristics)

HCl is a polar molecule and the chlorine atom closest to negative side because of electronegativity of the chlorine atom is higher than hydrogen so that it pulls shares pair of electrons from H atom as a result formation of partial positive charge on hydrogen and negative charge on chlorine atom.

Electronegativity Difference

Electronegativity is the tendency of an atom to attract lone pair of electrons towards itself from the sharing partner atom. It means atoms having higher electronegativity value than its bonding atom, the shared pair of electrons are not centralized i.e. shared electrons in the bond are more or lesser closer to the atoms having higher E.N value.

Electronegativity difference is a very important factor to determine the polarity of any molecules either polar or nonpolar. According to Pauli scale, if the electronegativity difference between two atoms is between 0.5 to 2.0, it is considered as a polar bond between them. In HCl molecule,

Electronegativity of H= 2.2

Electronegativity of Cl= 3.16

Electronegativity difference= 3.16-2.2= 0.96

As mentioned above, if E.N difference between two atoms is more than 0.4, it is considered as a polar bond and E.N difference between H and Cl is 0.96 so the bond between them is a polar covalent bond.

Lewis Structure & Molecular Geometry

HCl is a heteronuclear diatomic molecule in which a total of 8 valence electrons are available for Lewis structure i.e. hydrogen has one and chlorine has 7 valence electrons. Both chlorine and hydrogen share one-one electrons at the time of H-Cl bond formation.

is HCl polar or nonpolar? and geometry and lewis structure of HCl
As Hydrogen chloride is a heteronuclear diatomic molecule, it has a linear geometry. Here chlorine attracts the shared pair of electrons, causing a partial positive charge on hydrogen and a negative charge on chlorine.  

Dipole Moment

For any molecule being polar or nonpolar, the net dipole moment is the primary factor. Molecules having net dipole moment zero are known as a nonpolar molecule and having net dipole moments are considered as a polar molecule.

The net dipole moment is the product of dipole charge and distance between the atoms. It means the higher the electronegativity difference between the atoms, the higher the partial charge will be, as a result, the dipole moment is also higher. HCl has the net dipole moment 1.03 D and the bond length is 127 pm.

Electron Density

Electron Density is defined as the probability of the shared pair of electrons to present at a dedicated position within the molecule. But due to differences in electronegativity, the shared pair of electrons stay closer to the atom has a higher E.N value. In HCl, electrons are closer to the chlorine atom due to its higher E.N value. It means the chlorine atom has higher electron density and the chances of finding electrons are higher closer to the Cl atom in the HCl molecule.

Solubility Principle

According to the solubility principle “likes dissolve in likes”, means polar molecules dissolve in polar solvents and nonpolar molecules dissolve in nonpolar solvents. As HCl is a polar molecule, it dissolves in polar solvents like water.

Clarify your doubts

Is HF Polar or Nonpolar?

Is HI Polar or Nonpolar?

Is HBr Polar or Nonpolar?

Sources of Hydrogen Chloride (HCl)

1. Naturally, Hydrogen Chloride is found in our stomach which helps in the digestion of food i.e. acts as an acidifying agent human body.

2. It can be produced directly by the reaction of chlorine gas with water. But for laboratory and large industrial purposes, it is mostly prepared by the reaction of sodium chloride (NaCl) and sulphuric acid (H2SO4).

Properties of HCl

  • It is colorless, non-flammable with an acrid odor gas. It is also a poisonous and corrosive hazard gas because it can easily react with most of the metals to form explosive hydrogen gas causes severe pain burns and irritation to the eye and mucous membranes.
  • It has a molar mass of 36.46 g/mol with a density of 1.49 g/L and the net dipole moment is 1.05 D.
  • It has a higher dissociation constant i.e. H+ ion in the reaction so that it has a strong acidic nature.

Uses of Hydrochloric acid (HCl)

  • It is used in the production of batteries, photoflash bulbs, fireworks and many more electronics accessories.
  • In daily life, it is used to remove metal stains and leaning stones and tiles because of their corrosive nature.
  • It is also used to control the PH of the solution in many pharmaceutical products manufacturing and also used to purify table salts.

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