Question

Ch2Cl2 and CH3CH2NH2 are both polar but one of them is insoluble in water. How do I know which one is insoluble?

Answer 1

they're both soluble in water to an extent. DCM is less soluble though

Answer 2

@aaronq thanks for your reply :) would you be able to explain why DCM is less soluble? I can't seem to find an answer to it.

Answer 3

it has to do with polarity, because of the interactions (intermolecular forces) with water.

ethylamine is more polar and thus has stronger dipole-dipole attractions with water (hydrogen bonds, actually), this is energetically (in terms of enthalpy) a more favourable interaction - the energy of the system goes down (and is more stable) when these bonds form).

DCM is less polar, such that dipole-dipole forces with water are not considered hydrogen bonds. This means a less favourable interactions with water than ethylamine has, thus less solubility.

Answer 4

thanks a lot : )! @aaronq