Identify the predominant intermolecular forces in each of the given substances.

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Answer

General guidance

Concepts and reason
When two atoms or molecules approach each other, some attractive forces are developed between the nucleus of one atom and the electrons of other atom. There is a change in the electron distribution within a molecule. These interactions between the neighboring molecules or atoms are called intermolecular forces.

Fundamentals

London-dispersion forces are weak and exhibited by all the molecules. Hydrogen bonding is strong and exhibited by the molecules which have 0-H, N-H, or F-Hbond. Dipole-dipole interactions are moderate and exhibited by the molecules with a net dipole.

Step-by-step

Step 1 of 2

The given compounds are as follows: ОН
NH, H,0
Сн,сосн,
Сн,
сн,сHCH CH,COOCH,has dipole-dipole interactions and dispersion forces. InH,O, NHz, and C,H,OH, hydrogen bonding is present because of 0-H and N-Hbonds. They also have dipole-dipole interactions and dispersion forces. In , only dispersion forces are present.

In these compounds, methyl acetate, , ammonia, water, and propyl alcohol have polar covalent bonds. Hence, they have dipole-dipole interactions. Methane is non-polar. Dispersion forces are present in all molecules. Hydrogen bonding is possible when a hydrogen atom is bonded with more electronegative atom like O, N, or F.

Step 2 of 2

The order of the strength of intermolecular forces is as follows: Hydrogen bonding > Dipole-dipole > London or dispersion forces Hence, the predominant interactions in CH,COOCH,are dipole-dipole interactions. The predominant interactions in H,O, NH,, and CH CH(OH)CH,are hydrogen bonding. The predominant interactions in are London or dispersion interactions.

The predominant intermolecular forces present in these substances are as follows: Hydrogen bonding
Dipole-dipole
Dispersion (London)
forces
H2O
NHz
CH4
ОН
CH3COCHZ
CH3CHCHZ


As ionic interactions are stronger than the other interactions, in ionic interactions are predominant. Although dipole-dipole interactions are present inH,O, NH,, and CH CH(OH)CH,, present, hydrogen bonding is predominant in these molecules. In, both hydrogen boding and dipole-dipole interactions are absent. Hence, dispersion forces are predominant in this molecule.

Answer

The predominant intermolecular forces present in these substances are as follows: Hydrogen bonding
Dipole-dipole
Dispersion (London)
forces
H2O
NHz
CH4
ОН
CH3COCHZ
CH3CHCHZ

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