Hi does anyone know why is NH3 induced dipole forces?

Question

anonymous · Answer

is it because of the 2 unpaired electrons?

jfraser · Answer

an induced dipole force is an $inter$molecular force, meaning it only occurs $between$ molecules. By itself, $NH_3$ doesn't exert intermolecular forces, unless there is another molecule nearby.

By itself, $NH_3$ is a dipole, because of the lone pair of electrons on the central nitrogen.

When near another molecule, the dipole on the ammonia can $induce$ a dipole in a neighboring molecule that's not polar by itself, but only while they're near each other.

anonymous · Answer

So when NH3 has any interaction with another molecule, it will be induced dipole?

anonymous · Answer

If I understand correctly

anonymous · Answer

Am I right @JFraser ?

jfraser · Answer

it CAN BE, but it depends on what the other molecule is

anonymous · Answer

let's say for instance with LiBr

jfraser · Answer

LiBr is an $ionic$ substance, so the interaction will be ion-dipole

anonymous · Answer

so when will it be induced dipole then?

anonymous · Answer

NH4 is induced

jfraser · Answer

try a molecule like $CO_2$

anonymous · Answer

because it's induced dipole as well?

jfraser · Answer

|dw:1421325337336:dw|

jfraser · Answer

$CO_2$ is a non-polar molecule

anonymous · Answer

right sorry

jfraser · Answer

when a molecule of $CO_2$ is brought near a molecule of $NH_3$, the lone pair on the ammonia can $induce$ a temporary dipole in the $CO_2$ by pushing some of its electrons out of the way

jfraser · Answer

|dw:1421325476661:dw|but only so long as the two molecules are $CLOSE$ to each other