Answer :
To determine the dominant intermolecular force between ethane molecules ([tex]$C_2H_6$[/tex]), we first need to understand the nature of the ethane molecule:
1. Molecular Structure of Ethane:
Ethane ([tex]$C_2H_6$[/tex]) consists of two carbon atoms bonded together, each carbon atom being attached to three hydrogen atoms. The carbon-carbon bond and the carbon-hydrogen bonds are covalent.
2. Polarity of Ethane:
In ethane, the bonding electrons in the carbon-carbon bond are shared equally between the two carbon atoms because both carbon atoms have the same electronegativity. Similarly, the carbon-hydrogen bonds are nearly non-polar because the difference in electronegativity between carbon and hydrogen is very small. Therefore, ethane is a non-polar molecule.
Given these points, let’s assess the possible intermolecular forces:
1. Ion-Dipole Forces:
Ion-dipole forces occur between an ion and a polar molecule. Since ethane is non-polar and does not contain ions, ion-dipole forces are not applicable here.
2. Dispersion Forces (also known as London Dispersion Forces or Van der Waals Forces):
Dispersion forces are temporary attractive forces that occur when electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles. These forces are present in all molecules, whether they are polar or non-polar, and are the only intermolecular forces present in non-polar molecules like ethane.
3. Dipole-Dipole Forces:
Dipole-dipole forces are attractions between the positive end of one polar molecule and the negative end of another polar molecule. Since ethane is non-polar, dipole-dipole forces are not relevant here.
4. Hydrogen Bonding:
Hydrogen bonding is a specific, strong type of dipole-dipole interaction that occurs when hydrogen is covalently bonded to a highly electronegative atom (such as nitrogen, oxygen, or fluorine) and is attracted to another electronegative atom. Ethane does not contain N, O, or F, so hydrogen bonding does not occur in ethane.
Based on this analysis, the dominant intermolecular force between ethane molecules is dispersion forces.
Therefore, the correct answer is:
```
dispersion forces
```
1. Molecular Structure of Ethane:
Ethane ([tex]$C_2H_6$[/tex]) consists of two carbon atoms bonded together, each carbon atom being attached to three hydrogen atoms. The carbon-carbon bond and the carbon-hydrogen bonds are covalent.
2. Polarity of Ethane:
In ethane, the bonding electrons in the carbon-carbon bond are shared equally between the two carbon atoms because both carbon atoms have the same electronegativity. Similarly, the carbon-hydrogen bonds are nearly non-polar because the difference in electronegativity between carbon and hydrogen is very small. Therefore, ethane is a non-polar molecule.
Given these points, let’s assess the possible intermolecular forces:
1. Ion-Dipole Forces:
Ion-dipole forces occur between an ion and a polar molecule. Since ethane is non-polar and does not contain ions, ion-dipole forces are not applicable here.
2. Dispersion Forces (also known as London Dispersion Forces or Van der Waals Forces):
Dispersion forces are temporary attractive forces that occur when electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles. These forces are present in all molecules, whether they are polar or non-polar, and are the only intermolecular forces present in non-polar molecules like ethane.
3. Dipole-Dipole Forces:
Dipole-dipole forces are attractions between the positive end of one polar molecule and the negative end of another polar molecule. Since ethane is non-polar, dipole-dipole forces are not relevant here.
4. Hydrogen Bonding:
Hydrogen bonding is a specific, strong type of dipole-dipole interaction that occurs when hydrogen is covalently bonded to a highly electronegative atom (such as nitrogen, oxygen, or fluorine) and is attracted to another electronegative atom. Ethane does not contain N, O, or F, so hydrogen bonding does not occur in ethane.
Based on this analysis, the dominant intermolecular force between ethane molecules is dispersion forces.
Therefore, the correct answer is:
```
dispersion forces
```
