Which bond would break first.

Moderators: Chem_Mod, Chem_Admin

janeane Kim4G
Posts: 31
Joined: Thu Sep 27, 2018 11:28 pm

Which bond would break first.

Postby janeane Kim4G » Sun Nov 25, 2018 2:42 am

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?

Krista Mercado 1B
Posts: 51
Joined: Thu Sep 27, 2018 11:26 pm

Re: Which bond would break first.

Postby Krista Mercado 1B » Sun Nov 25, 2018 2:46 am

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.

Julia Go 2L
Posts: 48
Joined: Sat Sep 29, 2018 11:17 pm
Been upvoted: 1 time

Re: Which bond would break first.

Postby Julia Go 2L » Sun Nov 25, 2018 7:59 am

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.

Megan_Ervin_1F
Posts: 59
Joined: Thu Sep 27, 2018 11:18 pm

Re: Which bond would break first.

Postby Megan_Ervin_1F » Sun Nov 25, 2018 9:16 pm

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?

405021651
Posts: 46
Joined: Tue Nov 14, 2017 3:03 am

Re: Which bond would break first.

Postby 405021651 » Sun Nov 25, 2018 9:31 pm

would the sigma bond be weaker one so therefor break first??

Ethan Yi 1K
Posts: 49
Joined: Thu Sep 27, 2018 11:28 pm

Re: Which bond would break first.

Postby Ethan Yi 1K » Sun Nov 25, 2018 9:54 pm

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.

Yukta Italia 3I
Posts: 31
Joined: Thu Sep 27, 2018 11:24 pm

Re: Which bond would break first.

Postby Yukta Italia 3I » Mon Nov 26, 2018 3:08 pm

If pi bonds are weaker than sigma bonds then why are double and triple bonds stronger than single bonds?

Sapna Ramappa 1J
Posts: 45
Joined: Thu Sep 27, 2018 11:24 pm

Re: Which bond would break first.

Postby Sapna Ramappa 1J » Mon Nov 26, 2018 5:57 pm

Yes, the pi bond would break first, because it has less strength (the electron density is more spread out within pi bonds).

Hadji Yono-Cruz 2L
Posts: 52
Joined: Thu Sep 27, 2018 11:26 pm

Re: Which bond would break first.

Postby Hadji Yono-Cruz 2L » Tue Nov 27, 2018 1:56 pm

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.

Searra Harding 4I
Posts: 55
Joined: Thu Sep 27, 2018 11:29 pm

Re: Which bond would break first.

Postby Searra Harding 4I » Tue Nov 27, 2018 11:24 pm

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.

davidryan3f
Posts: 46
Joined: Thu Sep 27, 2018 11:23 pm

Re: Which bond would break first.

Postby davidryan3f » Sun Dec 02, 2018 11:48 pm

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.

305117729
Posts: 30
Joined: Thu Sep 27, 2018 11:16 pm

Re: Which bond would break first.

Postby 305117729 » Fri Dec 07, 2018 9:56 pm

pi bonds will break first, as they are weaker than sigma bonds.


Return to “Sigma & Pi Bonds”

Who is online

Users browsing this forum: No registered users and 1 guest