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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Gameofketones on May 03, 2019, 11:27:19 AM

Title: Octet rule
Post by: Gameofketones on May 03, 2019, 11:27:19 AM

During the electrophilic substitution in phenol at Ortho and para positions, one of the structure in each satisfies octet rule. One of the structure is attached below. Can anyone please explain how it satisfies octet rule ?

Title: Re: Octet rule
Post by: Babcock_Hall on May 07, 2019, 02:47:46 PM

It is a forum rule (see Red Link above) that you must show your attempt at solving a problem before we can help you.  What would constitute a violation of the octet rule in your judgment?

Title: Re: Octet rule
Post by: Gameofketones on May 08, 2019, 12:39:44 PM

In the structure 1b Oxygen has a positive charge. So how can it satisfy octet rule when it has lost 1 e- ?

Title: Re: Octet rule
Post by: mjc123 on May 08, 2019, 12:47:24 PM

It hasn't lost an electron. It has shared a pair of electrons with (what I presume is) the carbocation in 1a. Those electrons still count in its valence tally.

Title: Re: Octet rule
Post by: Gameofketones on May 08, 2019, 12:55:50 PM

So the carbocation doesn't satisfy octet rule because Oxygen is the donor and hence it cannot be counted in carbon's valency?

Title: Re: Octet rule
Post by: Babcock_Hall on May 08, 2019, 02:09:14 PM

Shared electrons still count.

Title: Re: Octet rule
Post by: mjc123 on May 09, 2019, 06:53:13 AM

The carbocation 1a does not satisfy the octet rule because the +ve carbon has only 6 valence electrons (it has an empty p orbital). In 1b, the oxygen shares one of its lone pairs with the carbon to form a pi bond. This pair therefore counts for both O and C, and both satisfy the octet rule. The formal positive charge sits on O.