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Why does hydrogen iodide have a low melting point??
Compared to what? :colonhash:
Titanium!? Carbon Dioxide!?:redface:

I'm just going to spurt out some chemistry at you and hope it works.:biggrin:

Not relevant to your question:
Iodine has a-lot of electrons compared to the other Halogens above it, therefore it shall have stronger Van der waal forces due to the higher Mr.

Relevant to your question:
However, Iodine also has more shielding than the Halogens above it, therefore the Electrostatic force of attraction between the nucleus and electrons will be weaker due to the shielding, thus giving Hydrogen Iodide a low melting point.:smile:
Reply 2
Avatar for Farzana12
Farzana12
OP
9
Original post by Bulletzone
Compared to what? :colonhash:
Titanium!? Carbon Dioxide!?:redface:

I'm just going to spurt out some chemistry at you and hope it works.:biggrin:

Not relevant to your question:
Iodine has a-lot of electrons compared to the other Halogens above it, therefore it shall have stronger Van der waal forces due to the higher Mr.

Relevant to your question:
However, Iodine also has more shielding than the Halogens above it, therefore the Electrostatic force of attraction between the nucleus and electrons will be weaker due to the shielding, thus giving Hydrogen Iodide a low melting point.:smile:


Thank you :smile:)) and it doesnt say anything about comparing it to another compound.
Original post by a_m15
Thank you :smile:)) and it doesnt say anything about comparing it to another compound.


Forgot to add, due to that weakened force of attraction between the nucleus and the electrons, the Covalent bond is weaker?

No problem.
Reply 4
Avatar for Pigster
Pigster
20
Original post by Bulletzone
the Electrostatic force of attraction between the nucleus and electrons will be weaker


This doesn't affect melting point.

HI has a low MP as it has a simple molecular lattice with weak IMF.

The difference in electronegativities is only fairly small, so the permanent dipole dipole attraction is quite small and since it has quite a few e-, the instantaneous dipole induced dipole attraction is of a similar size to the pdd. Together, they make the IMF reasonably large, but still lower than molecules with H-bonding.
Reply 5
Avatar for Farzana12
Farzana12
OP
9
Original post by Pigster
This doesn't affect melting point.

HI has a low MP as it has a simple molecular lattice with weak IMF.

The difference in electronegativities is only fairly small, so the permanent dipole dipole attraction is quite small and since it has quite a few e-, the instantaneous dipole induced dipole attraction is of a similar size to the pdd. Together, they make the IMF reasonably large, but still lower than molecules with H-bonding.


Thank you! :smile:

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