So, is CHCl3 polar or nonpolar? Yes, CHCl3 is polar due to its tetrahedral molecular structure and difference between the electronegativity of C, H and, CL. Chlorine atoms are more electronegative than carbon and hydrogen and lie at three vertices of the pyramid and pull the negative charge to its direction making it a polar molecule with a dipole in a downward direction. Chloroform is a very reactive substance as it reacts with air and light to form a poisonous gas carbonyl chloride ie; phosgene gas. This gas was used during world war for killing. Therefore, chloroform is safely stored in dark closed bottles up to its brim. It is also considered as a powerful anesthetic. The molecular mass of CHCl3 is 119.37 g·mol−1. It can be calculated as below Mol mass of CHCl3 = 1* 12(Mol mass of C) + 1 * 1(Mol mass oh H) + 3 * 35.4(Mol mass of Cl) = 119.37 g·mol−1 If we talk about the chemical composition of CHCl3, it consists of 1 Carbon, 1 Hydrogen, and 3 Chlorine atoms. Carbon is the central atom in the molecule of CHCl3 surrounded by hydrogen and chlorine atoms. The shape of the molecule is tetrahedral ie; hydrogen at top and chlorine atoms at three vertices in the base of the pyramid. All four bonds are single covalent and all atoms get stabilized with electronic configuration. The electronegativity of hydrogen is 2.2, chlorine is 3.16 and that of carbon is 2.55. Therefore C-H and C-Cl bonds are polar. In the C-H bond, carbon pulls the negative charge to its side and in C-Cl bonds, chlorine pulls the negative charge (electrons) to its side as chlorine is more electronegative than carbon. Due to unequal electronegativity and tetrahedral geometrical shape, there exists an unequal distribution of charge on atoms of the CHCl3 molecule.
Polar versus Nonpolar Molecule
The polarity of a molecule can be checked by keeping various factors in mind. The molecules that are covalently bonded can be polar as well as nonpolar. Let us check what differences the polar and nonpolar molecules actually make. Polar Molecules: The molecules that have their dipole moment value equals to non zero are polar molecules as they have some permanent dipole moment. These molecules do not have an equal distribution of charge across its molecule. The electronegativity of atoms in these molecules differs from each other. The covalent bond formed by two atoms tends to be polar if they both differ in their electronegativity. The geometry of polar molecules is distorted ie; asymmetric due to which they have uneven charge distribution. The geometrical shape of these molecules is symmetric in most of the cases. Few examples of polar molecules are HCN, SF4, etc. You can check out the reason for the polarity of SF4. Nonpolar Molecules: these types of molecules always have zero value of their dipole moment. The distribution of charge across these molecules is uniform. The electronegativity of atoms in these molecules do not differ from each other ie; have equal influence on bonded electron pair. The covalent bond formed by two atoms tends to be nonpolar if they have equal electronegativity. The geometrical shape of these molecules is symmetric in most of the cases. Some of the examples of nonpolar molecules are CS2, CO2, etc. You can check out the reason for the non-polarity of CS2.
Why is the CHCl3 Polar?
Chloroform or trichloromethane is polar due to the below reasons. The polarity of molecules means that molecules contain two opposite poles ie; negative and positive. In a chemical covalent bond, the atom that has a higher intensity of negative charge becomes a negative pole and another atom becomes a positive pole. In CHCl3, chlorine is more electronegative than hydrogen and carbon due to which electron density on chlorine increases and becomes a negative pole, and hydrogen and carbon denote positive pole. In addition to this, the shape of CHCl3 is tetrahedral having carbon on top and chlorine atoms at three vertices of the base of the pyramid. As a result, all three chlorine atom gives a net dipole in a downward direction. Therefore, chloroform is a polar substance.
How to check the polarity of a molecule?
If you want to check the polarity of a molecule, you must note down the below points. Electronegativity: the term electronegativity denotes the strength of an atom to attract the bonded electron pair to its side. More the electronegativity of an atom, more strongly it pulls the electron. If there is a difference between the electronegativity of two atoms forming a covalent bond, the bond tends to be polar. The polarity of a covalent bond is directly proportional to the difference between their electronegativity. So, you must note down the electronegativity of both atoms and compare them in order to check the extent of polarity. Geometrical shape: The shape of a molecule is also an important factor to check the polarity of a molecule. It is usually seen that the polar molecules have an asymmetric shape due to which there is an uneven distribution of charge across its atoms. On the other hand, the nonpolar molecules are symmetric in shape. Below is the image of the geometrical 3 D structure of the CHCl3 molecule.
Dipole Moment: the dipole of a molecule is the measure of its polarity. The polarity of a molecule is directly proportional to its dipole moment. It is the product of the charges on atoms and the difference between the centers of positive and negative charges. Its SI unit is Debye and is denoted by D. D = Q * R
Properties of CHCl3
At room temperature, it exists as a colorless liquid with a sweet smell. At a temperature of 25 °C, its density is 1.489 g/cm3. Its melting point is −63.5 °C or −82.3 °F and its boiling point is 61.15 °C or 142.07 °F. It is soluble in water. Its solubility in water at 20 °C is 8.09 g/L. The vapor pressure of CHCl3 at 25 °C is 25.9 kPa. At 20 °C, its acidity is 15.7 PKA. The molecular structure of chloroform is tetrahedral.
Uses of CHCl3
Chloroform is used as a good solvent for alkaloids, iodine, fats, and other substances. Chloroform is widely used for the manufacturing of refrigerant gases like Freon refrigerant R-22. This gas is used in electronics equipment like refrigerators, air conditioning. This is also used for medical purposes like used as an anesthetic during medical surgeries. On exposure to air and light, chloroform produces a poisonous gas known as phosgene.
Conclusion
Chloroform consists of 1 carbon, 1 hydrogen, and 3 chlorine atoms having tetrahedral shape. The chlorine atoms are at three vertices of the base of the pyramid. And the electronegative of chlorine is more than hydrogen and carbon due to which it pulls the negative charge slightly more towards its side. As a result, the dipole originates in a downward direction resulting in a polar CHCl3 molecule. So guys, if you have any queries about the polarity of CHCl3, feel free to ask in the comment section. I will reach out to you soon.
