2. in which of the following pure substances will hydrogen bonding be an important intermolecular force? 1)…

2. in which of the following pure substances will hydrogen bonding be an important intermolecular force? 1) dichloromethane, ch₂cl₂, 2) ch₃ch₂oh, 3) methylamine, (ch₃nh₂), 4) trimethylamine, n(ch₃)₃\na) 2 and 3\nb) all\nc) none\nd) 3 and 4\ne) 1 and 2

2. in which of the following pure substances will hydrogen bonding be an important intermolecular force? 1) dichloromethane, ch₂cl₂, 2) ch₃ch₂oh, 3) methylamine, (ch₃nh₂), 4) trimethylamine, n(ch₃)₃\na) 2 and 3\nb) all\nc) none\nd) 3 and 4\ne) 1 and 2

Answer

Explanation:

Step1: Recall hydrogen - bonding criteria

Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom (N, O, F) and there is another electronegative atom (N, O, F) in the vicinity to act as a hydrogen - bond acceptor.

Step2: Analyze dichloromethane ($CH_2Cl_2$)

In $CH_2Cl_2$, hydrogen is bonded to carbon. Carbon is not a highly electronegative atom like N, O, or F. So, no hydrogen bonding.

Step3: Analyze ethanol ($CH_3CH_2OH$)

In $CH_3CH_2OH$, the hydrogen atom is bonded to oxygen. Oxygen is highly electronegative. There can be hydrogen - bonding between ethanol molecules where the hydrogen of one ethanol molecule is attracted to the oxygen of another ethanol molecule.

Step4: Analyze methylamine ($CH_3NH_2$)

In $CH_3NH_2$, hydrogen is bonded to nitrogen. Nitrogen is highly electronegative. Hydrogen - bonding can occur between methylamine molecules where the hydrogen of one methylamine molecule is attracted to the nitrogen of another methylamine molecule.

Step5: Analyze trimethylamine ($N(CH_3)_3$)

In $N(CH_3)_3$, all the hydrogens are bonded to carbon. There is no H - N, H - O, or H - F bond. So, no hydrogen bonding.

Answer:

a) 2 and 3