What is the difference between induced dipole and dipole-dipole interactions?

Question

Then what is the distinction between hydrogen bonging and dipole-dipole?

Then what is the distinction between hydrogen bonding and dipole-dipole?

Answer 1

I think you've got it a little backward. In molecules like water, there is a permanent imbalance of electron distribution in the molecule. The oxygen atom in water always has a partial negative charge, and the hydrogens are always partially positively charged. This is so because the electronegativity of oxygen is very large compared to that of hydrogen. Therefore, when the two elements form covalent bonds in water, the electrons are pulled more strongly toward the oxygen atom, giving it a negative charge.

Because of this permanent polarity in the molecule, water molecules are dipoles (molecules with two regions of opposite charge). When two molecules of water interact, they do so through dipole-dipole interactions. That is, the positive part of one water molecule interacts with the negative part of a different molecule.

Induced dipole interactions occur between non-polar molecules. Because of the random movement of electrons in a molecule, just by chance the electron distribution will occasionally be lopsided, giving a slight positive charge to one part of the molecule and a slight negative charge to another part. If this molecule is close to another non-polar molecule, it's partially charged areas will push the electrons away in an adjacent molecule, inducing a dipole in the second molecule.

So, dipole-dipole interactions occur between molecules which are already polar, and induced dipole interactions occur between non-polar molecules, or between polar and non-polar molecules.

Check out a chemistry book for more details.

Answer 2

an induced dipole would occur in something like bromine or chlorine. it happens when the molecule (e.g Br or Cl) approaches a strong positive area of another molecule like a C atom (a carbocation) and the electrons are pulled towards the positive centre. This causes an unequal distribution of electrons in the Br or Cl molecule.
dipole dipole interactions are caused by the constant movement of electrons within a molecule where at one point a part of a molecule will be slightly negative and a part of another molecule will be slightly positive and so they will be attracted to each other for a split second before the electrons move around and the same thing happens with another molecule.