general conceptual question

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bgiorgi_3A
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Joined: Wed Sep 30, 2020 9:50 pm

general conceptual question

Postby bgiorgi_3A » Tue Dec 08, 2020 8:55 am

Hey guys! I have a general question. So when we are given two compounds and asked to determine which is the stronger acid, what should we look at first?
This is a pretty open ended question, but any feedback would help!

John Pham 3L
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Re: general conceptual question

Postby John Pham 3L » Tue Dec 08, 2020 9:06 am

I usually look at whether the acid is a binary acid first.
For binary acids (HCl, HBr, etc), you can look at the bond lengths and determine which are the longest. The longer the bond, the easier to break and the more acidic.

If it isn't a binary acid, then you can use EN to determine acidity.
The bond with Hydrogen should be the same in all molecules so EN would be used to determine the delocalization of e- and the more stable anion.
- Example: HClO vs HBrO, HClO would be the stronger acid since the e- are more delocalized and weakens the H-O bond

Andrew Wang 1C
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Re: general conceptual question

Postby Andrew Wang 1C » Tue Dec 08, 2020 11:23 am

I tend to first look at the bond that is being broken when an acid loses a H+, and comparing them to each other. The longer that bond is, the stronger the acid.

If the bond being broken is the same across the compounds being compared, I would look at which compound has the more stable anion. There are multiple ways to do this, like observing resonance, greater electronegativity, or larger size.

CesarLec1
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Re: general conceptual question

Postby CesarLec1 » Tue Dec 08, 2020 9:50 pm

Well first I classify if there are any strong acids present then I would see which molecule has the weaker bond with the H proton that is going to break off and the one with the weaker bond I classify as being the stronger one.

Isaac Wen
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Re: general conceptual question

Postby Isaac Wen » Tue Dec 08, 2020 11:29 pm

I look at the bond length between the atom connected to H. If it's longer then it that means the bond can be broken more easily, which means it's a stronger acid. I also look at the electronegativity of the atom connected to H.

MichaelRaad_1F
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Re: general conceptual question

Postby MichaelRaad_1F » Tue Dec 08, 2020 11:29 pm

We can look at bond length and electronegativity of the central atom of the molecule.

Madisen Brown -1C
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Re: general conceptual question

Postby Madisen Brown -1C » Fri Dec 11, 2020 4:19 pm

To determine the stronger acid or base I usually refer to the list of strong acids and bases from the sapling website and base my order on that list. Here's the link for the list if needed. I've found it to be very resourceful: https://sites.google.com/site/chempendi ... cids-bases

Jiapeng Han 1C
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Re: general conceptual question

Postby Jiapeng Han 1C » Sat Dec 12, 2020 4:12 am

With regard to exam, you should really remember some of the most widely-known strong acid. These include: HClO4, HI, HBr, HCl, H2SO4, HNO3. To classify whether an acid is strong or weak, you should look at how easily the H atom would be lost. Weak A-H bond will result in a strong acid since the H atom will be lost very easily. Also, the more stable the resulting anion, the more acidic an acid is.

Erika Sosa-Cruz 1J
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Re: general conceptual question

Postby Erika Sosa-Cruz 1J » Sat Dec 12, 2020 10:26 am

I think we could just look at the bond length.

305405193
Posts: 69
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Re: general conceptual question

Postby 305405193 » Tue Dec 15, 2020 8:12 pm

Usually I would think about the hydrogens attached or the OH's attached to determine whether it is more on the acidic or basic side, but I do have trouble determining whether it would be a strong or weak acid or base.


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