Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: davedicky on July 29, 2014, 06:58:35 PM
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Hey guys,
First time posting here, please let me know if it's in the wrong subforum.
This is a question from an exam I printed out that my University supplied.
I'm a tad confused by it, and am seeking clarification.
9, b: Which of the following bonds is ionic, which is polar covalent and which is nonpolar.
Cl-Cl
H-Cl
O-Cl
Cl-Cl has an electronegative difference of 0, so it is non polar.
H-Cl has an electronegative difference of 0.96.
O-Cl has an electronegative difference of 0.28.
None of these differences are ionic bonds. They all demonstrate mainly nonpolar bonds to my understanding.
Out of the three options, H-Cl is more polar than the rest, so that would be my choice of a polar covalent molecule.
An ionic bond is between a non-metal and a metal.
O-Cl are both non metals, and only have an electronegative difference of 0.28 (All of them are non-metals = None of them are ionic*)
Would the answer be that there are 2 Polar Covalent molecules (as O-Cl isn't entirely non-polar) and 1 Non-Polar molecule?
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Probably more suitable for general chemistry forum.
You are correct that Cl-Cl would form a nonpolar covalent bond. I guess strictly speaking you're right about the other two as well. But still you seem to have some confusion about bond what polarity is because of where you said "they all demonstrate mainly nonpolar bonds". So, what would be your definition of a polar bond?
(Hydrogen is often considered to be a metal for many purposes, by the way, and I wouldn't get too caught up in metals vs. nonmetals for questions like this. There are better ways to think about it.)
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Note that the question asks about bonds, not about molecules.
Would the answer be that there are 2 Polar Covalent molecules (as O-Cl isn't entirely non-polar) and 1 Non-Polar molecule?
That would mean you have three molecules in the question - as far as I can tell, you don't. HCl and Cl2 are molecules, but I have never seen OCl - that is, OCl- anion exists, but not a neutral OCl.
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Cl-Cl is nonpolar
H-Cl is ionic bond because of big electronegative difference
O-Cl is covalent bond and it is also polar, because O is more electronegative
Just a note, this is question about bonds, it does not have to be molecule, it can be a part of a molecule.