Polarity, as found in compounds, is a state in which a compound’s positive and negative poles are separated by an electric charge separation.
This is caused by the unequal sharing of valence electrons between two or more atoms in a molecule due to differences in electronegativity (the ability of an atom in a chemical bond to attract electrons towards itself).
It takes into account the physical features of the compounds, such as boiling and melting points, solubility, surface tension, and molecular interactions.
Is CH3Cl a polar or non-polar compound? Yes, Chloromethane (CH3Cl) or Methyl chloride (CH3Cl) is a polar molecule. Because Cl is more electronegative than carbon, the C-Cl covalent bond has unequal electronegativity, resulting in a charge separation and a net dipole.
Polar molecules are those with two ends, similar to the two poles of a magnet, that contain completely different types of charge.
For example, in HCl (Hydrogen Chloride), chlorine has a stronger electronegativity than hydrogen, drawing electrons strongly and resulting in a partial negative charge on itself and a partial positive charge on hydrogen.
The Lewis structure and Valence Bond Theory are the greatest tools for understanding the electronegativity of atoms with covalent bonds.
CH3Cl has a Lewis electron-dot structure.
The Lewis structure is used to anticipate a molecule’s properties and interactions with other compounds. It also sheds light on molecular physical characteristics.
It’s crucial to figure out how the atoms are arranged and how electrons are distributed around them in order to anticipate the structure of the molecule and explain its properties.
When looking at the Lewis structure of CH3Cl, you’ll notice that it’s an asymmetrical molecule. The unequal sharing of valence electrons causes the lack of symmetry.
When the structure is shown, the core atom is carbon, which is surrounded on one side by chlorine and on the other by hydrogen atoms.
We can determine the polarity of a molecule by drawing net dipole arrows on its molecular geometry. Let’s look at CH3Cl’s Lewis dot structure.
The entire number of valence electrons for CH3Cl must be calculated for the Lewis structure. According to the periodic table, carbon belongs to group 14 and has four valence electrons, while hydrogen belongs to group 1 and has just one, and we have three hydrogen atoms here.
Chlorine is a member of group 17 with seven valence electrons. We now have a total of 14 valence electrons after combining all of the valence electrons.
The central atom, carbon, stays at the centre. The hydrogen atoms are always on the exterior, and the highly electronegative chlorine will also be on the outside.
In addition, we must distribute these electrons throughout the structure.
There are 14 valence electrons in total, two of which must be placed between each atom to form a chemical connection. We consumed 8 valence electrons and now have only 6 valence electrons left. Let’s see if we’ve filled all of the atoms’ outer shells.
To complete the octet in the instance of chlorine, we add 6 extra valence electrons. Hydrogen just requires two valence electrons, which it already has. Chlorine requires 8 valence electrons, which it already has. The outer shells of each atom are now filled because all 14 valence electrons have been consumed.
Because chlorine is more electronegative than carbon and is closer to fluorine on the periodic table, a dipole arrow with a cross at one end can be drawn from Carbon to Chlorine [C-Cl].
The cross is located near the partially positive end of the molecule, whereas the arrow-head is located near the partially negative end.
Because the difference between hydrogen and carbon electronegativity levels is modest, the C-H bond is non-polar. As a result, no dipole arrow is drawn for C-H bonds.
We may deduce from Lewis structure that the C-Cl bond is polar, and hence the CH3Cl is polar and has a net dipole.
The dipole moment refers to the magnitude of a bond’s polarity. The higher the dipole movement and polarity, the greater the difference in relative electronegativity of the atoms.
VBT stands for Valence Bond Theory.
The Lewis electron dot structure is a two-dimensional depiction of the electron configuration in a molecule.
The Valence Bond Theory, on the other hand, considers the many forms of a molecule as well as the molecule model that come from the overlapping of atomic orbitals that hold bonding and non-bonding electrons.
Sp3 hybridization is observed in CH3Cl. How? Let’s get this straight.
In the instance of CH3Cl, the steric number is 4. The number of bonds and lone pairs at the core atom is known as the steric number. Between carbon and hydrogen, there are three sigma bonds, whereas between carbon and chlorine, there is one.
Since carbon has four valence electrons, all four have established bonds with three hydrogens and one chlorine atom, there are no lone pairs of electrons left.
As a result, 1+3=4=Sp3, i.e. 1s and 3p, will be hybridised.
Structure of CH3Cl
Let’s look into tetrahedral bonding in more detail. When just two half-filled p- orbitals are available for bonding, we must understand how carbon makes four bonds.
The orbital hybridization notion must be considered to understand this. This notion refers to the joining of atomic orbitals on a single atom to create new hybrid orbitals with geometry suitable for electron pairing in chemical bonds.
Carbon has four valence orbitals, one 2s and three 2p, as seen in the diagram below. When these are added together, they generate four equivalent hybrid orbitals.
Chloromethane’s structure and characteristics
Chloromethane has a tetrahedral structure with a bond angle of 109.5° and belongs to the haloalkanes or methyl halides category of chemical compounds.
The electron clouds on atoms around the central carbon atom repel each other, giving chloromethane its tetrahedral structure. It has an asymmetrical geometry to prevent dipoles from cancelling out due to opposing charges.
The boiling point of this molecule is -24°C (-11.2°F), and it transforms into a liquid under its own pressure. It freezes at -97.6°C and is used as a refrigerant in industry.
It has a density of 2.22 kg/m3 and a molecular mass of 50.49 g/mol. Both alcohol and water dissolve CH3Cl.
Methanol and hydrogen chloride are used to make methyl chloride in laboratories. Chlorination of methane can also be used to make it.
In the natural world, marine phytoplankton produces methyl chloride in oceans. Natural activities such as the burning of biomass in grasslands and forests also contribute to their formation.
When a mixture of chlorine and methane is exposed to ultraviolet light, a substitution reaction occurs, resulting in chloromethane.
One hydrogen is replaced by a chloro-group in methyl chloride, which emits a pleasant sweet odour only when present in high concentrations in the air and is otherwise difficult to detect.
Methyl chloride is a poisonous and combustible gas that is colourless and odourless (at low concentrations). Because of the polar covalent link that permits the molecule to operate as a good conductor, it is a weak electrolyte.
Because of the attraction between the positive and negative ends of the molecule, polar molecules like CH3Cl tend to interact more.
As more energy is required to evaporate the molecule, this connection causes a fall in vapour pressure and an increase in boiling point. Chloromethane interacts with other polar molecules via dipole-dipole forces.
Methyl chloride has a variety of industrial applications.
The refrigerant methyl chloride is well-known.
It’s utilised in the manufacturing of butyl rubber and elastomers as a catalyst or solvent.
It’s also commonly used as a chlorinator.
Petroleum refineries employ it as well.
It is used as a herbicide in fields.
Silicone polymers, silicone fluids, resins, and methyl celluloses are all made here.
It’s utilised in the production of pharmaceuticals and medicines.
It is used as a local anaesthetic in medical procedures.
Surfactants, medicines, and colours are all made from this basic material.
Hazards of Methyl Chloride Exposure
Methyl chloride is a dangerous and highly flammable chemical. Burning of wood, coal, and some polymers, cigarette smoke, and aerosol propellants are all sources of methyl chloride exposure.
This chemical can also be found in small amounts in lakes, streams, and drinking water.
A brief exposure to toxic quantities of methyl chloride in humans can have a devastating effect on the neurological system, resulting in coma, paralysis, convulsions, seizures, and death.
Dizziness, blurred vision, nausea, lethargy, vomiting, slurred speech, and lung congestion are some of the side effects. After inhaling the methyl chloride gas for a short time, some people develop problems with their heart rate, liver, and kidneys.
It has been observed that depending on the route and concentration of exposure, it might cause frostbite and neurotoxicity.
Chloromethane reactions that are significant
CH4 + Cl2—🡪 CH3Cl (Chloromethane) + HCl
CH3Cl + Cl2—🡪 CH2Cl2 (Dichloromethane) + HCl
Read more: Is Hydrogen Ion a Strong Acid?