lewis acid/base, acidity

[oral09]

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In topscore, question about lewis acid saying that BF3 is not lewis acid. But I am looking at the chem textbook, it showing me BF3 is lewis acid. Is this a mistake in topscore?

How do you tell the acidity of HCl , HBr, HI

Is that in increasing acidity order by HCL < HBr <HI
when do you compare acidity by the radius and electronegative?

thank you

 

[oral09]

One more quick question, why halogenated hydrocarbon is non-polar, how about CH3Cl, is this polar? and CHCl3 is polar too?

 

[TeamGuo]

In topscore, question about lewis acid saying that BF3 is not lewis acid. But I am looking at the chem textbook, it showing me BF3 is lewis acid. Is this a mistake in topscore?

How do you tell the acidity of HCl , HBr, HI

Is that in increasing acidity order by HCL < HBr <HI
when do you compare acidity by the radius and electronegative?

thank you

BF3 is a lewis acid, it can't be a lewis base since base donates its electrons and vice versa for acids, they accept electrons.

When you compare HF HCl HBr and HI, you can think about size. Since F- is pretty close to H's size and it's really electronegative, meaning it wants to stay close to H and grab the electrons off of H, so it does not want to dissociate = weaker acid since it does not readily dissociate like HI.

HI = I- is huge, so you can just strip the H off of I and I is less electronegative = so it readily dissociates.

Strong acids = completely dissociate readily.

So you have to use electronegativity and size when you compare the halogens.