Draw the structures of the following compounds and use dashed lines to indicate where they form hydrogen bonds to other molecules of the same kind: (i) formic acid

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Accepted Answer

All right. Hi everyone. So this question is asking us to give the structure of propionic acid and use dash lines to show the locations where it forms hydrogen bonds with other similar molecules. So recall first and foremost that the name of a carboxylic acid is derived from the hydrocarbon chain to which they are attached. So if we consider the the compound given here that propionic acid, that we can distinguish or determine how many carbons are in the parent chain specifically because of our prefix here pro as in propionic acid because recall that this comes from the word propane, which corresponds to a three carbon chain. And so the suffix A&E has been replaced by the modifier OIC acid to indicate what functional group is present. So because of this, I'm going to go ahead and draw a three carbon chain a little bit better. Actually, we have a three carbon chain and so on the first carbon at the very end is a carboxylic acid group, right? So carbon one here is connected to an oh group and it is also part of a carbonel or ac double plant O. So with this in mind, we can go ahead and consider hydrogen bonding for our propionic acid here recall that molecules capable of hydrogen bonding have to have a very specific structural feature molecules that can exhibit hydrogen bonding have hydrogen connected to a highly electron atom. Common examples are nitrogen oxygen or fluorine. And considering the structure of propionic acid, we can see that hydrogen or one hydrogen is connected to an electron atom, specifically oxygen. So therefore, propionic acid and all carboxylic acids actually do exhibit hydrogen bonding. So to understand the locations where hydrogen bonds form with other molecules, we have to distinguish between a hydrogen bond donor and an acceptor. Right, recall hydrogen bond donors are the regions in the molecule that contain the hydrogen atom attached to a highly electron atom. Whereas hydrogen bond acceptors are electron atoms with lone pairs of electrons. Now, in this case, carboxylic acids can be compared to alcohols in the sense that they do participate in hydrogen bonding with the o group being the hydrogen bond donor. But the unique thing here is that the car bono oxygen can participate as a hydrogen bond acceptor. So if I draw out two molecules of a carboxylic acid, I can see how this hydrogen bond works out, right, because the hydroxy hydrogen of one carboxylic acid molecule can interact with the carbo oxygen of another molecule. And the car bal oxygen of my first molecule interacts with the hydrogen of the second. So based on this right, we can see that hydrogen bonds stem from both the oh group of the carboxylic acid and the car bal oxygen, both parties participate in hydrogen bonding. And so both of them are going to receive dashed lights and there you have it. So here is your final answer. We have the structure of propionic acid with dash lines stemming from both the O group and the Carboni oxygen to showcase that hydrogen bonds form from those two regions. The hydroxy group is a hydrogen bond donor and the carbon oxygen is an acceptor. So with that being said, thank you so very much for watching and I hope you found this helpful.

Draw the structures of the following compounds and use dashed lines to indicate where they form hydrogen bonds to other molecules of the same kind: (i) formic acid

Verified video answer for a similar problem:

Key Concepts

Hydrogen Bonding

Molecular Structure of Formic Acid

Dashed Lines in Molecular Diagrams