CH2F2 is polar or non-polar? A common question can be easily answered as CH2F2 is a polar molecule because the structure of this molecule contains partial positive and negative charge depending upon the pull of electrons.
CH2F2:
It is a polar organic compound belonging to halogen-alkane class, chemically known as Difluoromethane, also called as R-32 or HFC-32. Difluoromethane is a colorless and also odorless gas present in the atmosphere. Also this gas is non-toxic and non-flammable.
Structure:
Structurally this molecule is an advanced form of Methane, except that the two hydrogens of methane (CH4) are replaced with two fluorine atoms generating the chemical formula as CH2F2 i.e. hydrocarbon containing halogen atom with it. The molecular formula is 52.023g/mol.
Physical And Chemical Properties:
Melting Point: -52°C
Boiling Point: -136°C
Density: At 25°C; 0.961 and at 0°C (in liquid state); 1.502
Solubility: Insoluble in water whereas soluble in ethanol
Vapor Pressure: 1.26 e 4 mm of Hg at 25°C
Uses:
- One of the major use of Difluoromethane is as ‘Refrigerant’ as it has an excellent heat transfer performance during vaporization and condensation.
- It is used in air conditioners as well, in few countries.
POLARITY OF CH2F2:
The term Polarity can be briefly explained as the separation of electric charges in a molecule producing the dipole moment in it with two oppositely charged ions i.e. positive and negative. This is done by pulling of electron by the atoms.
Not all of them perform such activity, only the atoms with high electronegativity tends to attract the bonding electron pair towards themselves. This action causes the uneven distribution of electrons between the bonded atoms and leads to the formation of partial negative and positive charge on the molecule making it polar in nature.
The polarity of a molecule can be easily distinguished according to the Pauling Scale:
Non-polar molecule, when the difference between the electronegativity is less than 0.4.
Polar molecule, when the difference between the electronegativity is between 0.4 and 2.0.
Ionic molecule, when the difference between the electronegativity is greater than 2.0.
The question whether the CH2F2 is polar or non-polar, can be quite confusing. To clear your mind, the concept leading to the answer of the question is described below:
Polar Molecule:
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Atoms containing polar bonds between them form a polar molecule. This type of bond is formed when the difference between the electronegativity of participating atoms is greater than 0.4 and less than or equal to 2.0, which leads to the formation of partial positive and partial negative charge on the molecule.
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Not only this, the polar molecule can also be formed when the chemical bonds are arranged in such a way that the arrangement leads to more positive charge on one side than the other.
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These molecules are asymmetric in shape due to the presence of either electronegativity difference between atoms or presence of lone pair of electrons on central atom.
Following are some of the examples of polar molecule containing polar bond because of greater electronegativity difference:
S.No. | Name of Molecules | Molecular Formula | Electronegativity Difference |
---|---|---|---|
1 | Carbon Monoxide | CO | 0.89 |
2 | Hydrogen Fluoride | HF | 1.69 |
3 | Ethanol | C2H6O | 0.89 |
4 | Hydrochloric Acid | HCl | 0.96 |
5 | Chloromethane | CH3Cl | 0.66 |
6 | Potassium Bromide | KBr | 2.14 |
7 | Hydrogen Peroxide | H2O2 | 1.24 |
8 | Hydrogen iodide | HI | 0.46 |
9 | Methanol | CH3OH | 0.89 |
10 | Hydrogen Bromide | HBr | 0.76 |
Non-Polar Molecule:
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Similarly the atoms containing non-polar bonds between them form a non-polar molecule. This type of molecule contains no separate electrical charges which means that there are no positive or negative charge like polar molecules. The charges are evenly distributed all over the molecule.
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The non-polar bond is formed when the difference between the electronegativity of participating atoms is less than 0.4.
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These molecules are symmetric in shape due to no unshared pair of electrons.
Following are some of the examples of non-polar molecules having lesser or no electronegativity difference:
S.No. | Name of Molecules | Molecular Formula | Electronegativity Difference |
---|---|---|---|
1 | Oxygen gas | O2 | 0.0 |
2 | Benzene | C6H6 | 0.35 |
3 | Propane | C3H6 | 0.35 |
4 | Hydrogen gas | H2 | 0.0 |
5 | Ethylene | C2H4 | 0.35 |
6 | Nitrogen gas | N2 | 0.0 |
7 | Methane | CH4 | 0.35 |
8 | Bromine gas | Br2 | 0.0 |
9 | Hexane | C6H14 | 0.35 |
10 | Paraffin Wax | C30H62 | 0.35 |
Electronegativity:
It is one of the major atomic property depending upon the share of electrons. Electronegativity can be defined as;
“Tendency of an atom to attract the bonding pair of electrons towards itself.”
Electronegativity can be measured by a system called Pauling Scale. This value is never constant, it varies depending upon the ability to attract the electrons. Fluorine is considered as the most electronegative element whereas Caesium and Francium are the least electronegative element according to the scale.
Following are the electronegativity of some commonly used elements:
S.No. | Name of Elements | Symbol | Electronegativity |
---|---|---|---|
1 | Oxygen | O | 3.44 |
2 | Nitrogen | N | 3.04 |
3 | Sulphur | S | 2.58 |
4 | Fluorine | F | 3.98 |
5 | Hydrogen | H | 2.20 |
6 | Chlorine | Cl | 3.16 |
7 | Carbon | C | 2.55 |
8 | Sodium | Na | 0.93 |
9 | Calcium | Ca | 1.00 |
10 | Bromine | Br | 2.96 |
Partial Charges:
When charges are measured in the elementary charge units the non-integer charge is called as Partial Charge.
This type of charge appears due to unsymmetrical distribution of electron in a bond. It can also be called as ‘Net Atomic Charge’. Partial charge is represented by a Greek letter 𝛿. The positivity and negativity of charges depends upon the force of attraction of the two bonding atom.
The higher the electronegativity higher will be the force of attraction and partial negative will be the charge. Whereas lower negativity, lower will be the force of attraction and partial positive will be the charge.
Example: The HCl molecule contains Hydrogen and Chlorine atom with electronegativity values:
H = 2.20
Cl =
Due to higher value of electronegativity the Chlorine atom strongly pulls the electron towards itself gaining partial negative charge and giving partial positive to the hydrogen.
`𝛿+ H ---- Cl 𝛿-`
CH2F2 Polar Or Non-Polar:
To determine whether CH2F2 is polar or non-polar, first you have to know about the structure of the molecule.
It has a tetrahedral structure containing Carbon atom in the middle of the structure surrounding with the four other atoms, two of which are hydrogen and the other two are fluorine atoms. There is no lone pair of electron on the molecule. Whereas the electronegativity of the atoms are:
C = 2.55
F = 3.98
H = 2.20
The difference between the electronegativity of Carbon (central atom) and Fluorine is found to be:
`3.98 – 2.55 = 1.43`
The answer is greater than 0.4 which suggests that the molecule is definitely polar. This difference also indicates that the pull of electrons is more towards fluorine as compared to the carbon which results in formation of partial positive and negative charges. Also the presence of two fluorine atoms shows that the molecule has slightly stronger dipole moment.
Summary:
Hence it is quite clear that CH2F2 molecule is a polar molecule containing polar bond with electronegativity difference of 1.43, giving partial positive charge to Carbon atom and partial negative charge to Fluorine atom.
Polarity Of Other Molecules:
Other than CH2F2 being a polar molecule, there are some other molecules which are illustrated below:
CO2 Polar Or Non-Polar:
Carbon dioxide is a colorless gas present in the atmosphere in trace amounts. Structurally it is a linear molecule and is composed of a single Carbon atom and two Oxygen atoms. The bonding between both of the atom is covalent bonding which means that either the molecule is having polar bond or non-polar bond.
The electronegativity of the bonded atoms are:
C = 2.55
O = 3.44
The difference between them is found to be:
`3.44 – 2.55 = 0.89`
It suggests that the molecule should contain positive and negative charges and dipole moment. But in this molecule this is not the case, as the molecule is linearly arranged the structure can be shown as:
O === C === O`
The effect of partial negative charges from both side of the Carbon cancel each other out giving the zero dipole moment. Hence, making the molecule Non- polar despite the electronegativity difference.
NH3 Polar or Non-Polar:
NH3 is commonly known as Ammonia gas. It is a colorless gas with strong pungent smell.
Most of the ammonia produced is used in agriculture and as refrigerant gas. From it’s formula it is quite clear that a single central Nitrogen atom is surrounded by three Hydrogen atoms.
Considering the first factor i.e. the structure of molecule, the odd number of bonding atom indicates that the structure is trigonal not linear proving the polar nature of molecule.
As far as other factor is concerned, the electronegativity of the atoms participating is:
N = 3.04
H = 2.20
And the difference between these values are:
`3.04 – 2.20 = 0.84`
The value is above or greater than 0.4 which also proves that the NH3 molecule is polar molecule.
H2O Polar or Non-Polar:
The world revolves around water, it is a basic necessity of life. Water molecule bears two Hydrogen atoms and one Oxygen atom.
According to the number of atoms it seems like that the case would be identical to Carbon dioxide but the difference arises in the arrangement of atom. The structure of water is non-linearly arranged. In the Carbon dioxide molecule the structure is linear due to which the two opposite end atoms cancel each other’s effect.
Looking forward to the other factor that is of electronegativity difference, the value of E.N of bonding atoms are:
H = 2.20
O = 3.44
And the difference would be;
`3.44 – 2.20 = 1.24`
Hence, also proving the polar nature of molecule.
Summary:
The CH2F2 is polar because of electronegativity difference on the other hand the CO2 is non-polar because of its structure although it does have electronegativity difference. This suggests that polarity of the molecule not only depends upon the electronegativity but also upon the arrangement of the atoms.
FREQUENTLY ASKED QUESTION:
Is ch2f2 tetrahedral?
Yes, the structure of CH2F2 i.e. difluoromethane is tetrahedral which helps or supports the dipole effect of molecule. The two fluorine and the two hydrogen atoms are tetrahedrally arranged around the central carbon atom.
Does ch2f2 dissolve in water?
CH2F2 is highly insoluble in water. Although it is said that polar molecules are more soluble in polar solvents. CH2F2 is a polar molecule which could be soluble in H2O, a polar solvent. But, the difluoromethane lacks hydrogen bonding which leads to insolubility in water.
Is CCl4 polar or nonpolar?
CCl4 is chemically known as carbon tetrachloride. Although the molecule contains four chlorine atoms which are high electronegative in nature, the molecule is still non-polar. This is due to the orientation of atoms the four chlorine are arranged tetrahedrally around the central Carbon atom. This arrangement cause the cancelation of electronegative effect and the dipole moment, hence making the molecule non-polar.
Is O2 polar or nonpolar?
The diatomic molecules are always and always non-polar. This is due to the fact that they are linearly arranged and cancels each other’s electronegative effect (having the same E.N value). The O2 (Oxygen gas) is also an example of diatomic molecule.
Is ethanol polar or nonpolar?
Ethanol is a hydrocarbon with a chemical formula C2H5OH. The hydrocarbons are mostly non-polar due to the presence of carbon and hydrogen atom and their low electronegativity difference. But in this case the presence of Oxygen atom which is an electronegative element, the molecule converts into polar because of greater difference of E.N.
CONCLUSION
The question whether a molecule is polar or non-polar such as CH2F2 polar or non-polar? can be easily understood. CH2F2, possessing tetrahedral structure and a difference of 1.43 in the electronegativity, is a polar molecule.
This suggests that polarity can be judged on the basis of following factors:
1. Difference between the electronegativity values
2. Structure of molecule or Orientation of atoms
These two factors can identify the type of bond and molecule too.