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As Chemistry - Ionic Bonding

Why are ionic compounds soluble in water, but insoluble in organic solvents
Reply 1
Organic solvents are non-polar, while ionic compounds are polar. The reason water can dissolve them is because water is very rarely pure, so it is nearly always likely to have some ions in there, which will make it polar. It's also because oxygen is electronegative so water will pretty much always be affected by magnetism.
Hence, you can put a magnet next to running tap water and the stream of water will be pushed away or pulled in slightly, based on the charge. It's all to do with charges and attractions, if there's no charge the ionic compound will not break up and will therefore, not dissolve. Hope this helps :smile:
(edited 8 years ago)
Reply 2
Original post by Guy123
Organic solvents are non-polar, while ionic compounds are polar. The reason water can dissolve them is because water is very rarely pure, so it is nearly always likely to have some ions in there, which will make it polar. It's also because oxygen is electronegative so water will pretty much always be affected by magnetism.
Hence, you can put a magnet next to running tap water and the stream of water will be pushed away or pulled in slightly, based on the charge. It's all to do with charges and attractions, if there's no charge the ionic compound will not break up and will therefore, not dissolve. Hope this helps :smile:

Yes thanks that helped a lot :smile:
As mentioned earlier. It's due to the polar nature of water molecules. This is down to electronegativity (which you'll cover in AS) - Electronegativity is the relative ability of an atom to attract electrons in a covalent bond. In principle all bonds are 'covalent' including ionic bonds, but because of electronegativity one atom may attract electrons much more strongly than the other, and is thus virtually in sole possessions of these electrons (creating ions!)

In H2O, the bonds are called 'polar covalent' - This is because Oxygen has a stronger electronegativity than Hydrogen but not SO strong that it's an ionic bond. Instead the electrons are just closer to the Oxygen atom, so the Oxygen atom becomes 'slightly negative' and the Hydrogen atom becomes 'slightly positive' (represented by delta +/- symbols).

Because of this, the Oxygen atoms will be attracted to the positive ions in an ionic lattice, and vice versa with Hydrogen. I hope I helped! :smile:
Reply 4
Original post by High Stakes
As mentioned earlier. It's due to the polar nature of water molecules. This is down to electronegativity (which you'll cover in AS) - Electronegativity is the relative ability of an atom to attract electrons in a covalent bond. In principle all bonds are 'covalent' including ionic bonds, but because of electronegativity one atom may attract electrons much more strongly than the other, and is thus virtually in sole possessions of these electrons (creating ions!)

In H2O, the bonds are called 'polar covalent' - This is because Oxygen has a stronger electronegativity than Hydrogen but not SO strong that it's an ionic bond. Instead the electrons are just closer to the Oxygen atom, so the Oxygen atom becomes 'slightly negative' and the Hydrogen atom becomes 'slightly positive' (represented by delta +/- symbols).

Because of this, the Oxygen atoms will be attracted to the positive ions in an ionic lattice, and vice versa with Hydrogen. I hope I helped! :smile:

Ah ok, I've literally just read this in the As Level revision guide. Thanks a lot guys!
Reply 5
Original post by Hannie16
Yes thanks that helped a lot :smile:


You're welcome :wink:

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