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Which bond would break first.

Posted: Sun Nov 25, 2018 2:42 am
by janeane Kim4G
Realistically, in a double bond of one pi and one sigma bond, which bond would break first? I would think it’s the pi bond, but I have no idea why, can someone elaborate?

Re: Which bond would break first.

Posted: Sun Nov 25, 2018 2:46 am
by Krista Mercado 1B
The pi-bond would break first since pi-bonds are weaker than sigma-bonds. This is because the side-by-side overlap in a pi-bond is smaller and weaker than the end-to-end overlap in a sigma bond.

Re: Which bond would break first.

Posted: Sun Nov 25, 2018 7:59 am
by Julia Go 2L
When a double bond breaks, pi bonds will always break first.

Pi bonds are weaker than sigma bonds. This is because sigma bonds have head-on overlapping while pi bonds only have lateral overlapping. The end-to-end axial overlap of electrons attracts the nuclei to form a strong bond. On the other hand, the electron density is more spread out in pi bonds and therefore, has weaker bonds.

Also, sigma bonds are stronger because there is a larger region of overlapping orbitals.

Re: Which bond would break first.

Posted: Sun Nov 25, 2018 9:16 pm
by Megan_Ervin_1F
So, sigma bond is stronger than pi bond. However, in a double bond there is a pi and sigma bond. I thought double bonds were stronger than single bonds but a single bond would only have a sigma bond. Is the reason that double bonds are stronger than single bonds because double bond has both a sigma and pi bond whereas a single bond just has a sigma bond?

Re: Which bond would break first.

Posted: Sun Nov 25, 2018 9:31 pm
by 405021651
would the sigma bond be weaker one so therefor break first??

Re: Which bond would break first.

Posted: Sun Nov 25, 2018 9:54 pm
by Ethan Yi 1K
the pi bond will break first because it is weaker than the sigma bond (less overlap).
a double bond is stronger than a single bond because it has a sigma AND pi bond rather than just a sigma bond.

Re: Which bond would break first.

Posted: Mon Nov 26, 2018 3:08 pm
by Yukta Italia 3I
If pi bonds are weaker than sigma bonds then why are double and triple bonds stronger than single bonds?

Re: Which bond would break first.

Posted: Mon Nov 26, 2018 5:57 pm
by Sapna Ramappa 1J
Yes, the pi bond would break first, because it has less strength (the electron density is more spread out within pi bonds).

Re: Which bond would break first.

Posted: Tue Nov 27, 2018 1:56 pm
by Hadji Yono-Cruz 2L
Pi bonds would break first because their electrons are more spread out than those of sigma bonds. The electrons in a sigma bond are directly between the two nuclei and are harder to break.

Re: Which bond would break first.

Posted: Tue Nov 27, 2018 11:24 pm
by Searra Harding 4I
Yukta Italia 3I wrote:If pi bonds are weaker than sigma bonds then why are double and triple bonds stronger than single bonds?

You are correct that pi bonds are weaker than sigma bonds. When considering why double and triple bonds are stronger than single bonds you should consider that all 3 types have one sigma bond. From here we look at the amount of pi bonds it has. A single bond has a sigma bond but a double bond has a sigma bond AND a pi bond. The amount simply makes it stronger as well as the length being shorter.

Re: Which bond would break first.

Posted: Sun Dec 02, 2018 11:48 pm
by davidryan3f
the pi bond would break first because it is weaker than the sigma bond. It has a lower dissociation energy so it will break first.

Re: Which bond would break first.

Posted: Fri Dec 07, 2018 9:56 pm
by 305117729
pi bonds will break first, as they are weaker than sigma bonds.

Re: Which bond would break first.

Posted: Fri Jul 12, 2019 8:23 pm
by 205458163
pi bond will break first, they are weaker than sigma bonds.

Re: Which bond would break first.

Posted: Tue Jul 16, 2019 1:39 pm
by jlinwashington1B
How would we be able to distinguish between the two? I know pie bonds show polarity, but I need a bit more clarification of sigma bonds>

Re: Which bond would break first.

Posted: Sun Oct 27, 2019 9:43 pm
by Veronica Lu 3L
the pi bond is much weaker than the sigma bond due to the differences in the way that they overlap. Therefore, the pi bond would break first.

Re: Which bond would break first.

Posted: Sun Oct 27, 2019 11:57 pm
by Aadil Rehan 1D
jlinwashington1B wrote:How would we be able to distinguish between the two? I know pie bonds show polarity, but I need a bit more clarification of sigma bonds>


Probably based on the length and energy of the bonds.