Hexane Structure, Characteristics: 53 Complete Quick Facts


In this article, “hexane structure”, different facts like structure, formal charge calculation, volatility, viscosity are discussed briefly.

Hexane is a colourless liquid having molecular mass 86.17 g/mol. It is a saturated hydrocarbon containing six carbon and fourteen hydrogen atoms. It is basically a volatile liquid having the melting point 690C used as extracting solvent. It is liquid due to presence of London-dispersion force.

Let’s focus on the following discussion topics on hexane.

How to draw Hexane lewis structure?

Lewis structure is one type of representation of molecular shape in which valence electrons play an important role and nonbonding electrons are shown around the respective atoms.

  1. Determining of valence electrons: Hexane is made of carbon and hydrogen atoms. Carbon has four valence electrons whereas hydrogen has only one valence electrons in their respective outer most shell
  2. Finding out the bonding electrons: Carbon atoms are attached with either two carbon and two hydrogen atoms (for inner chain carbon) and one carbon and three hydrogen atoms (for terminal carbon) with four single bonds. Thus, (4×2) = 8 electrons are involved in bond formation for each of the carbon atom.
  3. Finding out the nonbonding electrons: All the outer most shell electrons of hydrogen as well as carbon are used up in bonding. Therefore, no electrons are left as lone pairs or nonbonding electrons.
hexane structure
Hexane Lewis Structure.
Image Credit: Picryl

Hexane Lewis Structure Shape

Molecular shape or structure depends upon the hybridization of the central atom in absence of different repulsive factors like lone pair-lone pair repulsion, lone pair-bond pair repulsion and bond pair-bond pair repulsion.

The shape of hexane is tetrahedron like structure due to the hybridization sp3of central carbon atom. In hexane as all the valence electrons are used up in bond formation, no electrons are left as nonbonding electrons. Thus the shape of hexane is not deviated from its actual shape.

If carbon has any lone pairs or nonbonding electrons then the shape of hexane is violated from its actual geometrical shape due to presence of lone pair-lone pair and lone pair-bond pair repulsion. But hexane shows its actual geometrical structure as the central atom, carbon is sp3hybridized. Two of the four bonds of carbon atom lie on the plane of paper and the another two bonds are shown as upward or downward bond with respect to the plane of paper.

Three Dimensional Shape of Hexane.
Image Credit: Snappy goat

Hexane Lewis Structure Formal Charge

Formal charge calculation is done in chemistry to determine the most stable lewis structure of any compound.

  • Formal charge = Total number of valance electrons – number of electrons remain as nonbonded – (number of electrons involved in bond formation/2)
  • Formal charge of carbon of each of the carbon atom = 4 – 0 – (8/2) = 0
  • Formal charge of hydrogen of each of the hydrogen atom = 1 – 0 – (2/2) = 0

Carbon atoms are attached with the hydrogen atom as well as carbon atom through sigma bond. Terminal carbon atoms are bonded with three hydrogen and one carbon atom whereas the inner chain carbon atoms are attached with two carbon and two hydrogen atoms respectively.

Hexane Lewis Structure Angle

Angle denotes the bond angle which is also dependent on the hybridization of central atom and any repulsive factor (if present). Bond angle changes with the change of hybridization.

Hexane is a molecule having zero nonbonding electrons thus there is no chance of any repulsive factor like lone pair-lone pair repulsion, lone pair-bond pair repulsion. Only the hybridization of carbon atom directs the bond angle of hexane. According the hybridization of carbon atom (sp3), bond angle must be 109.50.

If any repulsion (mentioned in the previous stanza) is present, then the bond angle will deviate from its actual condition. Because the lone pair-lone pair repulsion or lone pair-bond pair repulsion closes or decreases the bond angle from its ideal bond angle. But due to absence of these repulsive factors, hexane shows its actual bond angle 109.50.

 Hexane Lewis Structure Octet Rule

Octet rule suggests a rule which states that any atom should possesses such electron configuration in its outer most shell which will match with the valence shell electron configuration of its nearest noble gas according to the periodic table.

Carbon atoms in hexane solely satisfies octet rule. It has four electrons in its outer most shell. After bond formation with neighboring carbon and hydrogen atoms, it achieves another four electrons in its valence shell which resembles with the electron configuration of its nearest noble gas Neon’s valence shell, in periodic table. Neon also has eight electrons in its outer most shell (2s2 2p6).

Hydrogen has one valence electrons. Its valency is two. After forming covalent bond with carbon atom, it also gains another electron shared with carbon atom. Thus, it also achieves the electron configuration of its nearest noble has, helium. Therefore, it follows duplet rule (having two electrons in valence shell).

Hexane Lewis Structure Lone Pairs

Lone pairs or nonbonding electrons are two similar term which indicated those type of valence electrons who are not participating in bond formation with another atoms. Lone pairs also help to determine the structure of anu molecule.

  • Nonbonded electron = Total number of valance electron – number of bonded electrons.
  • Nonbonding electron of carbon = 4 – 4 = 0
  • Nonbonding electron of hydrogen atom = 1- 1 = 0

Thus, hexane has no nonbonding electrons. All the electrons are used as bond formation.

Hexane Valence Electrons

Valence electrons are considered as the outer most shell electrons of an atom. They are the most loosely bound electrons because the attraction force of nucleus is least on the valence shell electrons.

Hexane consists of two different atoms, carbon and hydrogen. Carbon has total six electrons, among the six, four electrons are outer most shell. Hydrogen has one electron in its 1s orbital and it is the valence electron.

Therefore, total valence electrons present in hexane = (6×4) + (14×1) = 38.

Hexane Solubility

Solubility depends upon the nature of the solvent as well as solute. Nonpolar solute dissolves in nonpolar solvent whereas polar solute dissolves in polar solvent due to matching of nature.

Hexane is a nonpolar molecule with almost zero dipole moment and water is a polar molecule. The water molecules are associated with each other by strong intermolecular hydrogen bonding due to presence of highly electronegative oxygen atom. Thus, hexane can’t be soluble in water, but it is soluble in toluene, benzene and oil.

For the same reason hexane is not soluble in ethanol and NaOH as ethanol is a polar solvent and hexane is a nonpolar hydrocarbon.

Is Hexane an electrolyte?

 Electrolytes are those who can be dissociated into two opposite ions when dissolved in water. Electrolytes must be polar for dissociation into two different ions.

Hexane is not an electrolyte because it is not dissolved in water. It is a nonpolar molecule and made with carbon and hydrogen atoms. Therefore, it can’t be dissociated into two different ions, positive and negative ions and not able to conduct electricity.

Is Hexane acidic or basic?

Hexane is long chain molecule containing six carbon atoms. It is basically a neutral molecule having neutral pH (pH=7).

Is hexane saturated or unsaturated?

Saturation or unsaturation indicates the presence or absence of any double or triple bond or any ring in the molecular structure respectively. Six carbon atoms are attached with each other and with hydrogen atoms by single bonds.

Thus, there is no double or triple bond present in hexane molecule.

Is hexane corrosive?

No, hexane is not a very much harmful compound (corrosive means a highly reactive compounds that causes obvious damage to living tissues). But it causes some health hazards like inhalation exposure including dizziness, giddiness, nausea and headache in human beings. Consumption above a particular level of hexane creates some irritation in the eyes and throat etc.

Is hexane denser than water?

No, water is denser than hexane. Because the water molecules are densely packed with each other by strong intermolecular hydrogen bonding. But this type of hydrogen bonding is absent in hexane due to absence of any electronegative atom. Due to the strong hydrogen bonding, the intermolecular distance between the water molecules is decreased. Therefore, the density of water becomes high with respect to hexane.

 Is hexane dipole dipole?

Dipole is the separation of two opposite charges (positive and negative). Hexane is a nonpolar organic compound. Thus, there is no presence of any dipole. Being the nonpolar molecule only London dispersion force is present in hexane molecule.

Dipole-dipole interaction is only present in the polar molecule because charge separation can be observed in those molecules. Therefore, hexane is not a dipole.

Does hexane evaporate?

Evaporation of any substance depends upon the boiling point. Hexane has boiling point 690C. Due to absence of intermolecular hydrogen bonding or any strong attraction forces, the hexane molecules cannot be associated with each other. Thus, hexane evaporates quickly than heptane. Because London dispersion force is present in both the molecule. But the force is relatively stronger in heptane because of the greater molecular weight of heptane with respect to hexane.

Is hexane halogenated?

Compounds can be two different types-

  1. Halogenated
  2. Non-halogenated

Halogenated and non-halogenated compounds suggest presence or absence of halogen molecules like fluorine, chlorine, bromine, iodine.

Now, hexane is a molecule containing only carbon and hydrogen atoms. It is a long hydrocarbon chain. No halogen atoms (mentioned above) are present in the molecular structure of hexane. Thus, hexane is not a halogenated molecule.

Is hexane hydrophobic or hydrophilic?

Hydrophobic or hydrophilic nature is defined as the attraction or repulsion from the water molecules. Generally, alkanes are hydrophobic due to having almost zero dipole moment.

Hexane is also a nonpolar molecule with almost zero dipole moment. It is insoluble in water. Thus, it is hydrophobic in nature, repels the water molecules.

Is hexane more stable than cyclohexane?

The basic difference between hexane and cyclohexane is in the number of hydrogen atoms. Both the compounds have same number of carbon atoms (six). Hexane and cyclohexane have boiling point 690C and 80.740C respectively. Thus, hexane evaporates at faster rate than cyclohexane, which indicates that hexane molecules are more active than cyclohexane. The stability can also be explained by the combustion enthalpy. The enthalpy of combustion of hexane and cyclohexane are -4163 KJ/mol and -3919.6 KJ/mol.

Therefore, hexane liberates greater amount of energy than cyclohexane in combustion process. So, it can be concluded that cyclohexane is more stable than hexane.

Is hexane more polar than diethyl ether?

Polarity depends upon the electronegativity difference between the participating atoms and the orientation of the bonds with respect to each other.

Hexane is a symmetrical molecule having only carbon and hydrogen atoms. The electronegativity difference between carbon and hydrogen is not so high because both have a comparable electronegativity in Pauling scale. But diethyl ether contains highly electronegative oxygen and relatively lesser electronegative carbon and hydrogen atoms. The electronegativity difference between oxygen with carbon and hydrogen is comparatively high. Thus, diethyl ether has more polarity than hexane.

For the same reason, methanol, ethanol and ethyl acetate is more polar than hexane. Because all the substances contain highly electronegative oxygen atom.

Does hexane react with potassium permanganate?

Potassium permanganate or KMnO4is a strong oxidizing agent. But it does not react with the saturated hydrocarbons like alkane. Hexane is an alkane having no unsaturation. When potassium permanganate is mixed with hexane it does not mix with hexane. Both the solution can be easily distinguished and separated from each other.

Does hexane react with sulfuric acid?

Sulfuric acid does not take part in reaction with hexane. When sulfuric acid is added with hexane, it is also not mixed with hexane and can be easily distinguished from each other.

Does hexane react with bromine water?

In dark hexane does not react with bromine water due to absence of any unsaturation. But when exposed to light both the solution reacts with each other. Hexane is a colourless organic solvent and bromine is a brown coloured liquid. When both the solution reacts, bromine water is decolourised and a colourless solution is obtained.

Is hexane volatile?

Volatility depends upon the boiling point as well as the intermolecular forces present in the molecule. Hexane is volatile solvent because no strong intermolecular forces are present except weak London-dispersion force.  The boiling point of hexane 690C.

Is hexane more volatile than acetone?

No, acetone is more volatile than hexane. Though dipolar forces are present in acetone due to becoming a polar molecule. But London dispersion force in hexane predominates over the dipolar interaction.

London dispersion force in hexane is relatively strong because hexane is large molecule containing a long straight chain of six carbon atoms and this type of van der waals force also increases with increasing the molecular weight.

Acetone only contains two carbon, one oxygen and six hydrogen atoms. Thus, London dispersion force in hexane can easily exceed the dipolar interaction of acetone molecule.

But hexane is has more volatility than ethanol because of the intermolecular hydrogen bonding between the molecules of ethanol. Toluene is also less volatile than the hexane. The boiling point of toluene is 110.60C.

Is hexane more viscous than methane?

Viscous fluid is considered those fluids which has more flow resistance with comparing to the non-viscous fluid. For example, honey and ketch up.

Yes, hexane is more viscous than methane. Methane is a gaseous molecule whereas hexane is an organic liquid solvent. Methane has viscosity 11.13 µPa.s but hexane has viscosity 0.295 mPa.s.

Is hexane a good solvent?

Hexane is a very good solvent used for dissolving many organic substances. It is also used as extracting solvents of oil from seeds, fruits, nuts for its different qualities like-

  • Low boiling point
  • Low toxicity
  • Affordability

Hexane also works as cleaning agent in different industries.

Conclusion

From the above article it can be concluded that hexane is an organic saturated compound. It is volatile and nonpolar in nature. It is used in extraction of oils from fruits, nuts and seeds.

Aditi Roy

Hi..I am Aditi Roy, I have completed my graduation from University of Calcutta and am pursuing M.Sc in Chemistry from Techno India University. My area of specialization is on Inorganic Chemistry.

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