Relative Acidity

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Jamie2002
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Relative Acidity

Postby Jamie2002 » Fri Dec 11, 2020 3:13 pm

When determining relative acidity, do we consider bond length first or electronegativity? Which one is more important?

Steph Du 1H
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Re: Relative Acidity

Postby Steph Du 1H » Fri Dec 11, 2020 3:17 pm

If the bond being broken for the compounds you are comparing is different, you compare bond length (ex. HCl and HBr). If the bond being broken is the same, then you compare electronegativity (ex. CCl3COOH and CH3COOH).

Brianne Conway 1D
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Re: Relative Acidity

Postby Brianne Conway 1D » Fri Dec 11, 2020 5:06 pm

Steph Du 2B wrote:If the bond being broken for the compounds you are comparing is different, you compare bond length (ex. HCl and HBr). If the bond being broken is the same, then you compare electronegativity (ex. CCl3COOH and CH3COOH).


Thanks for that explanation, it really clears everything up nicely.

Rose_Malki_3G
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Re: Relative Acidity

Postby Rose_Malki_3G » Fri Dec 11, 2020 5:15 pm

First compare bond length. If bonds are the same in the compounds you are comparing then compare stability of the anions (so compare electronegativity)

Nathan Chu 3H
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Re: Relative Acidity

Postby Nathan Chu 3H » Fri Dec 11, 2020 7:40 pm

Bond length is mainly considered when comparing binary acids, such as HF, HCl, and HI. In this case, the acids with longer bonds will be stronger acids, as they have weaker bonds and can deprotonate easier.

Electronegativity and how well the conjugate base anion dilutes the negative charge is used when considering oxoacids, such as HOBrO2 and HOClO2. In this example, the HOClO2 acid is stronger because chlorine is more electronegative than Bromine. Because chlorine is more electronegative, it is able pull the electron density away from the O-H bond and allow it to deprotonate easier.

Jamie2002
Posts: 105
Joined: Wed Sep 30, 2020 9:55 pm

Re: Relative Acidity

Postby Jamie2002 » Fri Dec 11, 2020 11:37 pm

Nathan Chu 1J wrote:Bond length is mainly considered when comparing binary acids, such as HF, HCl, and HI. In this case, the acids with longer bonds will be stronger acids, as they have weaker bonds and can deprotonate easier.

Electronegativity and how well the conjugate base anion dilutes the negative charge is used when considering oxoacids, such as HOBrO2 and HOClO2. In this example, the HOClO2 acid is stronger because chlorine is more electronegative than Bromine. Because chlorine is more electronegative, it is able pull the electron density away from the O-H bond and allow it to deprotonate easier.


Thankyou so much! It's a lot clearer now :)

Jamie2002
Posts: 105
Joined: Wed Sep 30, 2020 9:55 pm

Re: Relative Acidity

Postby Jamie2002 » Fri Dec 11, 2020 11:37 pm

Rose_Malki_3L wrote:First compare bond length. If bonds are the same in the compounds you are comparing then compare stability of the anions (so compare electronegativity)


Thank you!

Jamie2002
Posts: 105
Joined: Wed Sep 30, 2020 9:55 pm

Re: Relative Acidity

Postby Jamie2002 » Fri Dec 11, 2020 11:38 pm

Steph Du 2B wrote:If the bond being broken for the compounds you are comparing is different, you compare bond length (ex. HCl and HBr). If the bond being broken is the same, then you compare electronegativity (ex. CCl3COOH and CH3COOH).


Thank you!


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