If a solid line represents a covalent bond and a dotted line...

If a solid line represents a covalent bond and a dotted line represents intermolecular attraction, which of the choices shows a hydrogen bond? H-H $H_4C \cdots H-F$ $H_2O \cdots H-CH_3$ $H_3N \cdots H-O-H$ Incorrect Answer

Transcript

00:01 Okay, we've got to compare these representations and determine which one shows a hydrogen bond.

00:06 So first we've got h3n, dot, dot, dot, hydrogen, oxygen, hydrogen.

00:17 Next we've got h2o, dot, dot, dot, h, c, h, c, h, and finally, let's see.

00:30 Okay, we've got h, h, yep, okay, and then h4c.

00:43 Okay, we'll recall what we need for a hydrogen bond.

00:49 We need a heteroatom hydrogen bond, so that is going to be anything but carbon and then a hydrogen.

00:58 So it could be nitrogen, hydrogen, oxygen, hydrogen, could be fluorine hydrogen.

01:04 So this is going to be a very polarized bond that's going to be negative, strongly partially negative on the heteroatom side and strongly partially positive on the protons.

01:17 And then paired with that, so this is our donor.

01:21 Paired with that, we need an acceptor.

01:24 And our acceptor is going to be any hetero atom that has lone pairs.

01:28 So one example might be water with a lone pair.

01:33 Or it could be ammonia with a lone pair.

01:36 Pair or it could be another atom of hydrofluic acid in this case right so we're looking for something like this and we can see that okay well here we've got nitrogen ammonia it has a lone pair and it's having a you know a long range interaction with this proton and the protons attached to a hetero atom so we know that this is partially positive and this is partially negative so this one looks good right the very first one that looks like a hydrogen bond to me.

02:13 Do any of the other ones look like hydrogen bonds? sort of...

Question

If a solid line represents a covalent bond and a dotted line represents intermolecular attraction, which of the choices shows a hydrogen bond? H-H $H_4C \cdots H-F$ $H_2O \cdots H-CH_3$ $H_3N \cdots H-O-H$ Incorrect Answer

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