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Solubility of organic compounds

For a substance to be soluble in water, does it have to be able to form hydrogen bonds or can it be soluble even though it only has van der waals and dipole dipole attractions?
Original post by fullmetal heart
For a substance to be soluble in water, does it have to be able to form hydrogen bonds or can it be soluble even though it only has van der waals and dipole dipole attractions?


If it's polar/ionic/permanent dipole, then it will be soluble.
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Avatar for Zeppto
Zeppto
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Like dissolves like. So if two things are polar (or non-polar), they will most likely dissolve each other. So no, solubility is not only dependent on the formation of hydrogen bonds (but substances can dissolve by forming hydrogen bonds). As long as the interactions are the same, the solute is soluble. Overall, polarity is the main factor that effects solubility in water, as the solute must be polar.
Original post by champ_mc99
If it's polar/ionic/permanent dipole, then it will be soluble.


I thought halogenoalkanes had a perminant dipole but the carbon - halogen bond wasn't polar enough for it to be soluble in water
Original post by fullmetal heart
For a substance to be soluble in water, does it have to be able to form hydrogen bonds or can it be soluble even though it only has van der waals and dipole dipole attractions?


In order for a solution to form, the intermolecular attractions between the solute and solvent must be greater than the attraction between solute molecules or the attraction between solvent molecules.
eg: two polar molecules will generally be soluble as they have permanent dipole-dipole forces exist between the H atoms with the Cl and Na with O as in NaCl and H2O.
Original post by fullmetal heart
I thought halogenoalkanes had a perminant dipole but the carbon - halogen bond wasn't polar enough for it to be soluble in water



Thats because halogenoalkanes are likely to have stronger van der waals forces between them unless it is a branched halogenoalkane.
Original post by fullmetal heart
I thought halogenoalkanes had a perminant dipole but the carbon - halogen bond wasn't polar enough for it to be soluble in water


It is polar enough. That's how you get substitution reactions: the haloalkane is dissolved in water.
Solubility, or rather miscibility, depends on a three-way struggle.

1. There are bonds between liquid A molecules
2. There are bonds between liquid B molecules
3. There are bonds between liquid A and liquid B molecules

For something to be soluble it has to form bonds strong enough to disrupt the bonding in the two pure phases, otherwise each component keeps itself to itself.

Haloalkanes can form polar bonds to ethanol which are strong enough to disrupt the H-bonding in ethanol, but its weak polar bonding to water is not strong enough to disrupt the stronger H bonding in water.

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