In liquid propanol,

CH3CH2CH2OH
which intermolecular forces are present?
a)Only dispersion and dipole-dipole forces are present.

b)Dispersion, hydrogen bonding and dipole-dipole forces are present.
c)Only hydrogen bonding forces are present.

d)Only dipole-dipole and ion-dipole forces are present.

All molecules have dispersion forces.

H atoms of one atom attracted to a highly electronegative element (F, Cl, O) of another provides hydrogen bonding.
Molecules that have one end more polar than the other are dipoles.

To determine the intermolecular forces present in liquid propanol (CH3CH2CH2OH), we need to consider the types of intermolecular attractions that can occur.

1. Dispersion forces (also called London dispersion forces or van der Waals forces): These forces arise from temporary fluctuations in electron distributions, leading to instantaneous dipoles. All molecules experience dispersion forces to some extent. However, the strength of these forces depends on the size and shape of the molecules involved.

In the case of propanol, the elongated and branched structure contributes to increased surface area and potential for better dispersion interactions.

2. Dipole-dipole forces: These forces occur between the positive end of one polar molecule and the negative end of another polar molecule. To determine if dipole-dipole forces are present, we need to examine the polarity of propanol.

In propanol, the oxygen atom is more electronegative than carbon, resulting in a polar C-O bond. The overall molecular structure of propanol is also polar due to the presence of the polar C-O bond and the C-H dipoles. Thus, propanol can exhibit dipole-dipole forces between its polar molecules.

3. Hydrogen bonding forces: These forces are a special type of dipole-dipole interaction that occur between a hydrogen atom bonded to an electronegative atom (such as oxygen, nitrogen, or fluorine) and another electronegative atom in a different molecule.

In propanol, there is a hydrogen atom bonded to an oxygen atom, forming an -OH group. Since oxygen is highly electronegative, it can create a strong polar bond with hydrogen, allowing for hydrogen bonding. Therefore, propanol is capable of forming hydrogen bonds as well.

Based on the analysis above, the correct option is (b) Dispersion, hydrogen bonding, and dipole-dipole forces are present in liquid propanol (CH3CH2CH2OH).

In liquid propanol (CH3CH2CH2OH), the intermolecular forces that are present are:

b) Dispersion, hydrogen bonding, and dipole-dipole forces.

Dispersion forces, also known as London dispersion forces or van der Waals forces, exist between all molecules and are due to temporary shifts in electron density.

Dipole-dipole forces are present because the propanol molecule has a polar bond between the oxygen and hydrogen atoms. These forces occur when the positive end of one molecule is attracted to the negative end of another molecule.

Finally, hydrogen bonding forces are present in propanol due to the presence of hydrogen bonded to an electronegative atom (oxygen) in the molecule. Hydrogen bonding is a stronger form of dipole-dipole interaction that occurs when hydrogen is bonded to fluorine, oxygen, or nitrogen.