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Carbocation Stability - Resonance & Rearrangement - Allylic & Vinylic Examples - Organic Chemistry
 
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This organic chemistry video tutorial explains how to determine which carbocation is most stable. It provides plenty of examples including allylic and vinylic carbocations using resonance structures to explain why allylic carbocations are most stable. It also provide examples of carbocations containing electron donating groups and electron withdrawing groups. It also discusses why tertiary carbocations are more stable than primary and secondary carbocations using terms such as hyperconjugation and the inductive effect.
Determining Carbocation Stability
 
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Now we’re going to discuss the most important intermediate of all organic chemistry, the carbocation. Watch more of this topic at ► http://bit.ly/28JcWXB Download this PDF: http://bit.ly/28JN5NR GET MORE CLUTCH! VISIT our website for more of the help you need: http://bit.ly/28JN2BU SUBSCRIBE for new videos: http://cltch.us/1axA33X --- LET'S CONNECT! Facebook: http://cltch.us/1JLgiSZ Twitter: http://cltch.us/1NLcKpu Instagram: http://cltch.us/1If5pb7 Google+: http://cltch.us/1E34o85 Clutch Prep = Textbook specific videos to help you pass your toughest science classes.
Views: 19267 Clutch Prep
TRICK to compare any Carbocation Stability - JEE||NEET||CBSE (IITian Faculty)(Hindi)
 
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"IITian Faculty" explains the above concept in entertaining and conceptual manner.
Views: 109601 Any Time Padhai Academy
Carbocation Stability Primary Secondary Tertiary Allylic and Benzylic
 
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Are you struggling with organic chemistry? Download my free ebook "10 Secrets To Acing Organic Chemistry" here: http://leah4sci.com/orgo-ebook/ http://leah4sci.com/organicchemistry/ presents Carbocation stability Part 1 This is an older video. For my new tutorials and associated quizzess visit this page: http://leah4sci.com/college-corner/organic-chemistry-video-and-quiz-library/ Please post questions/comments below or contact me via my website: http://leah4sci.com/contact/ Find me online: http://leah4sci.com FACEBOOK: http://facebook.com/leah4sci TWITTER: http://twitter.com/leah4sci
Views: 67721 Leah4sci
List The Following Carbocations In Increasing Order of Stability
 
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This video shows you how to list the following carbocations in order of stability.
GOC (Part 3): Stability of Carbocation
 
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This video deals with the stability of carbocation in detail. Link for notes: https://jeepmt.wordpress.com My completely *FREE Organic Chemistry* courses can be found here: https://unacademy.com/sachinranaIITB/organic-chemistry-playlist/SD3U0P4S Go access them. It's my guarantee these are the best courses you'll ever find in Organic Chemistry.
Carbocation Stability - Hyperconjugation and The Inductive Effect
 
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This organic chemistry video discusses two ways an electron donating group such as a methyl group can stabilize a carbocation - that is - by means of hyperconjugation and the inductive effect. This video explains the hyperconjugation and inductive effect with plenty of examples.
Stability of Carbocation:Solved Questions -in Hindi English Mix
 
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(GOC) Stability Of Carbocation/Carbanion/carbradical | Homolytic & Heterolytic Cleavage | NEET JEE
 
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SN1 exercises - Carbocation Stability
 
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For more, go to http://masterorganicchemistry.com SN1 - carbocation stability. Try these exercises yourself!
Carbanion Stability
 
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Methyl Carbanions are more stable than tertiary carbanions. Electron donating groups such as methyls can cause the carbanion to be less stable. The presence of electron withdrawing group such as Fluorine can be stabilize the negative charge of a carbanion.
Comparing Stability of Resonance structures - IITJEE Concepts in Hindi
 
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This video explains the above concept in entertaining and conceptual manner.
Views: 105936 Any Time Padhai Academy
Trick to Compare any Free radical stability - IITJEE concepts in Hindi
 
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"IITian Faculty" explains the above concept in entertaining and conceptual manner.
Primary, Secondary, Tertiary Carbocation & Ranking Their Stability
 
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DO NOT FORGET TO SUBSCRIBE! This video puts emphasis on ranking carbocations based on stability and the ability to participate in resonance.
Views: 1041 Kevan Science
Carbocation Stability - Hyperconjugation, Inductive Effect & Resonance Structures
 
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This organic chemistry video tutorial provides a basic introduction into carbocation stability. It discusses hyperconjugation and the inductive effect of electron donating groups and electron withdrawing groups. It also discusses carbocation stability using resonance structures. Subscribe: https://www.youtube.com/channel/UCEWpbFLzoYGPfuWUMFPSaoA?sub_confirmation=1 Access to Premium Videos: https://www.patreon.com/MathScienceTutor https://www.facebook.com/MathScienceTutoring/ New Organic Chemistry Playlist https://www.youtube.com/watch?v=6unef5Hz6SU&index=1&list=PL0o_zxa4K1BXP7TUO7656wg0uF1xYnwgm&t=0s
Carbocation Stability and Hyperconjugation in Organic Chemistry
 
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Visit our website for the notes of this lecture: https://knowbeetutoring.wordpress.com/ Get private tutoring from anywhere in the world, via your computer, from this instructor. He offers help in Organic Chemistry, General Chemistry, Physics, MCAT, PCAT, and DAT. SUBMIT AN MCAT PROBLEM AND I WILL SHOW YOU HOW TO SOLVE IT VIA VIDEO. FREE. VISIT WEBSITE FOR DETAILS. https://knowbeetutoring.wordpress.com/
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Stability of carbocations
 
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In this video I go over a strategy on how to identify the most stable carbocation intermediate to help us determine the product of a reaction.
Views: 3739 Alan Guo
The radical stability trend
 
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Radicals are unstable intermediates. So we’re going to have to discuss some ways to stabilize them. Unlike carbocations, allylic and benzylic radicals are ALWAYS most stable. Watch more of this topic at ► http://bit.ly/28KunWo Download this PDF: http://bit.ly/28KumSt GET MORE CLUTCH! VISIT our website for more of the help you need: http://bit.ly/28IFX6Z SUBSCRIBE for new videos: http://cltch.us/1axA33X --- LET'S CONNECT! Facebook: http://cltch.us/1JLgiSZ Twitter: http://cltch.us/1NLcKpu Instagram: http://cltch.us/1If5pb7 Google+: http://cltch.us/1E34o85 Clutch Prep = Textbook specific videos to help you pass your toughest science classes.
Views: 14190 Clutch Prep
Carbocation (Lightboard)
 
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Carbocation Stability: A comparison This organic chemistry video tutorial explains how to determine which carbocation is most stable. It also discusses why tertiary carbocations are more stable than primary and secondary carbocations using terms such as hyperconjugation and the inductive effect.
Views: 4036 Fun Man FUNG
Alkene Stability - Most Stable, Rank / Order - Cis & Trans Practice - Organic Chemistry
 
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This organic chemistry video tutorial shows you how to determine which alkene is most stable. It explains how to rank alkenes in order of increasing stability. It provides examples and practice problems such as conjugated alkenes / dienes and cis and trans E/Z isomers and alkenes in rings. Allenes and Cumulated Dienes are included as well.
3 Factors That Influence Carbocation Stability
 
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3 key factors that influence carbocation stability - substitution, resonance, and the presence of heteroatoms. From MasterOrganicChemistry.com [http://masterorganicchemistry.com]
Trick to Compare Any Carbanion Stability - JEE||NEET||CBSE (IITian Faculty)(Hindi)
 
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"IITian Faculty" explains the above concept in entertaining and conceptual manner.
Carbocations and Carbanions | General Organic Chemistry | Explained by IITian | Jee Mains & Advance
 
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Carbocations and Carbanions are some of the most important topics in General Organic Chemistry for Jee Mains & Advance. Carbocations:- Carbocations are the key intermediates in several reactions and particularly in nucleophilic substitution reactions. Structure of Carbocations : Generally, in the carbocations the positively charged carbon atom is bonded to three other atoms and has no nonbonding electrons. It is sp2 hybridized with a planar structure and bond angles of about 120°. There is a vacant unhybridized p orbital which in the case of CH3+ lies perpendicular to the plane of C—H bonds. Stability of Carbocations: There is an increase in carbocation stability with additional alkyl substitution. Thus one finds that addition of HX to three typical olefins decreases in the order (CH3)2C=CH2 greater CH3—CH = CH2 greater CH2 = CH2. This is due to the relative stabilities of the carbocations formed in the rate determining step which in turn follows from the fact that the stability is increased by the electron releasing methyl group (+I), three such groups being more effective than two, and two more effective than one. Stability of carbocations 3°greater 2° greater 1° greater CH3+ Electron release : Disperses charge, stabilizes ion. Further, any structural feature which tends to reduce the electron deficiency at the tricoordinate carbon stabilizes the carbocation. Thus when the positive carbon is in conjugation with a double bond, the stability is more. This is so, because due to resonance the positive charge is spread over two atoms instead of being concentrated on only one. This explains the stability associated with the allylic cation. The benzylic cations are stable, since one can draw canonical forms as for allylic cations. The benzyl cation stability is affected by the presence of substituents on the ring. Electron donating p-methoxy and p-amino groups stabilize the carbocation by 14 and 26 kcal/mole, respectively. The electron withdrawing groups like p-nitro destabilize by 20 kcal/mol. A hetero atom with an unshared pair of electrons when present adjacent to the cationic centre strongly stabilizes the carbocation. The methoxymethyl cation has been obtained as a stable solid CH3O+CH2SbF6-. Cyclopropylmethyl cations are even more stable than the benzyl cations. This special stability is a result of conjugation between the bent orbitals of the cyclopropyl ring and the vacant p orbital of the cationic carbon. That the carbocations are planar is shown by the fact that these are difficult or impossible to form at bridgeheads, where they cannot be planar. The stability order of carbocation is explained by hyperconjugation. In vinyl cations (CH2 = C+H), resonance stability lacks completely and these therefore are very much less stable. Carbanions Structure of Carbanions: A carbanion possesses an unshared pair of electron and thus represents a base. The best likely description is that the central carbon atom is sp3 hybridized with the unshared pair occupying one apex of the tetrahedron. Carbanions would thus have pyramidal structures similar to those of amines. It is believed that carbanions undergo a rapid interconversion between two pyramidal forms. There is evidence for the sp3 nature of the central carbon and for its tetrahedral structure. At bridgehead a carbon does not undergo reactions in which it must be converted to a carbocation. However, the reactions which involve carbanions at such centres take place with ease, and stable bridgehead carbanions are known. In case this structure is correct and if all three R groups on a carbanions are different, the carbanion should be chiral. All reactions therefore, which involve the formation of chiral carbanion should give retention of configuration. However, this never happens and has been explained due to an umbrella effect as in amines. Thus the unshared pair and the central carbon rapidly oscillate from one side of the plane to the other. Stability and Generation of Carbanions: The Grignard reagent is the best known member of a broad class of substances, called organometallic compounds where carbon is bonded to a metal lithium, potassium sodium, zinc, mercury, lead, thallium – almost any metal known. Whatever the metal it is less electronegative than carbon, and the carbon metal bond like the one in the Grignard reagent highly polar. Although the organic group is not a full-fledged carbanion – an anion in which carbon carries negative charge, it however, has carbanion character. Or organometallic compounds can serve as a source from which carbon is readily transferred with its electrons. On treatment with a metal, in RX the direction of the original dipole moment is reversed (reverse polarization). We Hope, you all will enjoy the lecture. Thanks Team IITian Explains
Views: 47191 IITian explains
Carbocation and Carbanion Relative Stability
 
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This video discusses the differences between the carbocation and the carbanion as regards to how they form and their relative stability.
Question 9 CHEM 2211exam3sp17 - carbocation stability ranking
 
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looks at the effects of hyperconjugation on the stability of carbocations
Carbocation... Types and stability
 
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Education
Views: 198 Chemistry Dose
Organic Chemistry Resonance Structures - Rules, Practice Examples, Formal Charge, Drawing Compounds
 
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This organic chemistry video tutorial shows you how to draw resonance structures. It provides the rules that you need to know along with plenty of examples and practice problems. It shows you how to calculate the formal charge of an element in a compound and it shows you how to determine the major resonance contributor and the minor resonance structure by identifying which resonance structure is more or less stable using principles such as electronegativity, atomic and ionic size, formal charge separation, aromaticity and octet sastifactory requirements. This video lecture explains why secondary carbocations are more stable than primary carbocations and why the reverse is true in the case of carbanions. It explains this concept using principles such as the inductive effect, hyperconjugation, and the presence of electron donating groups. This video lecture contains plenty of notes and examples for you to remember whenever your drawing resonance structures.
Which is more stable tertiary carbocation with 9 alpha H or benzyl carbocation?| Explained by IITian
 
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Hello Guys, Today we are going to discuss a very common misconception about stability of Benzyl and tert-Butyl Carbocation. Actual question is "Which is more stable tertiary carbocation with 9 alpha H or benzyl carbocation?" There are a number of approaches we can take to try and answer this question. We'll start by first comparing solvolysis rate data to see which carbocation is more stable in solution, and then we can look at thermochemical data to see how the carbocation stabilities compare in the gas phase. Solution Stability By comparing the rates at which two compounds solvolyze we can infer which compound leads to the more stable carbocation. For example, allyl chloride solvolyzes ~8.5 times faster than i-propyl chloride (1) in agreement with the idea that the allyl carbocation is more stable than the 2-propyl carbocation. Of course reactions must be run under conditions to minimize any non-solvolytic pathways (SN2) and insure that an SN1 mechanism is operating. At 45 C in 50% EtOH, t-butyl chloride solvolyzes almost 20,000 times faster than i-propyl chloride. This is in accord with the expectation that a tertiary carbocation is more stable than a secondary carbocation. we see that benzyl chloride solvolyzes 145 times faster than i-propyl chloride. at first glance this seems to tell us that (using isopropyl chloride as a common reference point) t-butyl chloride solvolyzes ~120 times (1.76x10000/145) faster than benzyl chloride. If we were to raise the reaction temperature to 50 C (supply more thermal energy to the reaction), this would tend to decrease the difference in relative rates. Similarly, since the dielectric constant of water is greater than the dielectric constant of ethanol, and since a higher dielectric constant facilitates ionization, if we were to rerun the second set of reactions in water-ethanol, both reaction rates would be enhanced and the difference in relative rates would decrease. So both the reaction temperature and solvent dielectric effects operate in the same direction; if we were to rerun this second set of reactions under conditions identical to the first set of reactions we would expect the relative rate to be something less than 145. If the relative rate for the second set of reactions is really 100 than t-butyl chloride would solvolyze ~176 times (1.76x10000/100) faster than benzyl chloride. If instead of 100, the relative rate for the second set of reactions is really only 10, then we would estimate that t-butyl chloride solvolyzes ~1,760 times (1.76x10000/10) faster than benzyl chloride. In any case, the t-butyl chloride solvolyzes faster than benzyl chloride, suggesting that the t-butyl carbocation is slightly more stable than the benzyl carbocation in solution. Reference:- Organic Chemistry, Maitland Jones, Jr, third edition, p. 585 Organic Chemistry, Maitland Jones, Jr, third edition, p. 658 Gas Phase stability:- (CH3)3C+ + H- → (CH3)3CH is exothermic by 231 kcal/mol. The corresponding reaction for benzyl cation C6H5CH2+ + H- → C6H5CH3 is exothermic by 234 kcal/mol. So it’s really close, and although they don’t give error bars in this source, the energies may be indistinguishable experimentally once error is taken into account. But if these energies are exact, t-butyl cation is a little more stable. *E.V. Anslyn and D.A. Dougherty, Modern Physical Organic Chemistry, Sausalito: University Science Books, 2006, page 88. -------------------------------------------------------------------------------------- Watch our other useful videos. Mesomeric Effect in Organic Chemistry | Explained by IITian Explains | Jee Mains, Advanced| NEET https://youtu.be/VhalncvcOio -------------------------------------------------------------------------------------------- Super-Concept of Inductive Effect | Explained by IITian | Jee Mains, Advanced | BITSAT | NEET |AIIMS https://youtu.be/iai9zGar2zk First Point of Difference Rule | Organic Chemistry | Explained by IITian | Jee Mains, Advance | NEET https://youtu.be/URBmaMusB60 ------------------------------------------------------------------------------------------- Tricks to Compare Stability of Resonating Structures | Explained by IITian | Jee Mains, Advance|NEET https://youtu.be/M6h7HBsWj0U ------------------------------------------------------------------------------------------ Thanks Team IITian Explains
Views: 7504 IITian explains
Carbocation Stability in Organic Chemistry Part - 1 | CHEMISTRY | JEE | NEET | IIT | By Chintan Sir
 
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Please watch: "Chemistry Physics New website Launch | CHEMISTRY | NEET | JEE | By Chintan Sir" https://www.youtube.com/watch?v=wKFxRixiKB8 --~-- The charged carbon atom in a carbocation is a "sextet", i.e. it has only six electrons in its outer valence shell instead of the eight valence electrons that ensures maximum stability (octet rule). Therefore, carbocations are often reactive, seeking to fill the octet of valence electrons as well as regain a neutral charge. One could reasonably assume a carbocation to have sp3 hybridization with an empty sp3 orbital giving positive charge. However, the reactivity of a carbocation more closely resembles sp2 hybridization with a trigonal planar molecular geometry. An example is the methyl cation, A carbocation may be stabilized by resonance by a carbon-carbon double bond next to the ionized carbon. Such cations as allyl cation CH2=CH–CH2+ and benzyl cation C6H5–CH2+ are more stable than most other carbocations. Molecules that can form allyl or benzyl carbocations are especially reactive. These carbocations where the C+ is adjacent to another carbon atom that has a double or triple bond have extra stability because of the overlap of the empty p orbital of the carbocation with the p orbitals of the π bond. This overlap of the orbitals allows the charge to be shared between multiple atoms – delocalization of the charge - and, therefore, stabilizes the carbocation. Hyperconjugation is also a stabilizing factor for carbocations. The empty pi orbitals of the carbon atom accepts a pair of electrons from the alpha carbon which then acquires the positive charge. More alpha hydrogens increases the stability of carbocation. Stability order also follows sp3 - sp2 -sp hybridization of the carbon atom bearing positive charge. In the NMR spectrum of a dimethyl derivative, two nonequivalent signals are found for the two methyl groups, indicating that the molecular conformation of this cation is not perpendicular (as in A) but is bisected (as in B) with the empty p-orbital and the cyclopropyl ring system in the same plane: In terms of bent bond theory, this preference is explained by assuming favorable orbital overlap between the filled cyclopropane bent bonds and the empty p-orbital. .
Views: 2200 CHEMISTRY JEE \ NEET
Carbocation Stability in Organic Chemistry Part - 3 | CHEMISTRY | JEE | NEET | IIT | By Chintan Sir
 
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Please watch: "Chemistry Physics New website Launch | CHEMISTRY | NEET | JEE | By Chintan Sir" https://www.youtube.com/watch?v=wKFxRixiKB8 --~-- Clearly, the tertiary carbocation is the most stable, as it is surrounded by three other carbon atoms that share the burden of its positive charge. Primary and especially methyl carbocations are rarely seen in organic reactions except under special circumstances like in the case of benzylic or allylic cations. Similarly, a tertiary benzylic cation is more stable than a secondary benzylic cation, which is more stable than the (primary) benzyl cation. Because the allyl and benzyl cations have delocalized electrons, they are more stable than other primary carbocations. Hyperconjugation is the stabilising interaction that results from the interaction of the electrons in a σ-bond (usually C-H or C-C) with an adjacent empty or partially filled p-orbital or a π-orbital to give an extended molecular orbital that increases the stability of the system.
acidic strength (all effects)
 
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I am giving full detail lecture of organic chemistry
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Carbocations and factors affecting stability
 
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http://chem-net.blogspot.gr/2013/02/carbocations-factors-affecting-their.html How carbocations are stabilized? What factors affect their stability?
Views: 81 koskal8192
carbocations and rearrangements
 
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More free lessons at: http://www.khanacademy.org/video?v=fv9h29ZChfI
How to determine which structure is most stable
 
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Often one of the resonance structures will be more stable, so it will contribute to the hybrid more than the others. Use the octet rule and electronegativity trends to determine the best placement of charges. (i.e. Fluorine is more stable with a negative charge than oxygen). Watch more of this topic at ► http://bit.ly/28J8zcy GET MORE CLUTCH! VISIT our website for more of the help you need: http://bit.ly/28J8tl3 SUBSCRIBE for new videos: http://cltch.us/1axA33X --- LET'S CONNECT! Facebook: http://cltch.us/1JLgiSZ Twitter: http://cltch.us/1NLcKpu Instagram: http://cltch.us/1If5pb7 Google+: http://cltch.us/1E34o85 Clutch Prep = Textbook specific videos to help you pass your toughest science classes.
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Markovnikov's rule and carbocations | Alkenes and Alkynes | Organic chemistry | Khan Academy
 
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Markovnikov's Rule and Carbocations. Figuring out which addition reaction is more likely. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/organic-chemistry/alkenes-alkynes/alkene-reactions/v/addition-of-water-acid-catalyzed-mechanism?utm_source=YT&utm_medium=Desc&utm_campaign=organicchemistry Missed the previous lesson? https://www.khanacademy.org/science/organic-chemistry/alkenes-alkynes/alkene-reactions/v/introduction-to-reaction-mechanisms?utm_source=YT&utm_medium=Desc&utm_campaign=organicchemistry Organic Chemistry on Khan Academy: Carbon can form covalent bonds with itself and other elements to create a mind-boggling array of structures. In organic chemistry, we will learn about the reactions chemists use to synthesize crazy carbon based structures, as well as the analytical methods to characterize them. We will also think about how those reactions are occurring on a molecular level with reaction mechanisms. Simply put, organic chemistry is like building with molecular Legos. Let's make some beautiful organic molecules! About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content. For free. For everyone. Forever. #YouCanLearnAnything Subscribe to Khan Academy’s Organic Chemistry channel: https://www.youtube.com/channel/UCNKPjijOc0WEJ7DIV_Vay3g?sub_confirmation=1 Subscribe to Khan Academy: https://www.youtube.com/subscription_center?add_user=khanacademy
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how to compare carbocation stability in GOC/Chemistry,General Organic Chemistry |
 
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B SC 1ST MECHANISM OF ORGANIC REACTIONS CARBOCATION,CARBOANION TYPES STABILITY STRUCTURE PART 5
 
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MECHANISM OF ORGANIC REACTIONS B SC FIRST MECHANISM OF ORGANIC REACTIONS CARBOCATION TYPES STABILITY STRUCTURE CARBOANION STABILITY DEFINE CARBOCATION TYPES OF CARBOCATION STRUCTURE OF CARBOCATION STABILITY ORDER OF CARBOCATION DEFINE CARBOANION TYPES OF CARBOANION STABILITY OF CARBOANION STRUCTURE OF CARBOANION A+ JULANA EDUCATION HUB EDUCATING FOR BETTER FUTURE A PLUS INSTITUTE OF SCIENCE APJ INSTITUTE OF SCIENCE
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carbocations: formation and stability
 
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Carbocations and factors affecting their formation and stability is presented in this video-tutorial. The main topics covered in this video tutorial are the following: What is a carbocation – Definition Types of carbocations Factors that stabilize carbocations Examples A carbocation is a species where a carbon atom bonds to three other atoms and has a positive charge. Carbocations are electron deficient species and therefore very reactive and unstable. The simplest carbocation is the methyl cation CH3+ The methyl cation has only three bonds to the positively charged center, only six electrons in the outer shell and is electron deficient. It is planar trigonal with an empty p orbital. The methyl cation is so unstable that is rarely formed even in the gas phase. Most stable carbocations have extra stabilization mainly from electron donating functional groups but even these relatively stable cations cannot be detected in normal solutions by NMR. Carbocations are characterized as primary, secondary or tertiary depending upon the number of bonds that the carbon atom with the positive charge has with other carbon atoms. As the methyl or in general the alkyl groups are electron-donating tertiary carbocations show extra stability and different reactivity than the primary. Primary carbocations have a carbon atom with a positive charge that has only one bond with another carbon atom Secondary carbocations have a carbon atom with a positive charge that has two bonds with two carbon atoms. Tertiary carbocations have a carbon atom with a positive charge that has three bonds with three carbon atoms A few other interesting cases of carbocations are the following: Allylic carbocations: Carbocation where the carbon atom with the positive charge is immediately adjacent to a carbon-carbon double bond. Benzylic carbocations: Carbocation where the carbon atom with the positive charge is immediately adjacent to a benzene ring. Vinylic carbocations: Carbocation where the carbon atom with the positive charge is part of an alkene. Aryl carbocations: Carbocation where the carbon atom with the positive charge is part of a benzene ring. Carbocations are by their very nature unstable species. However, there are certain factors that stabilize them such as: Resonance Inductive effects Rearrangements Please share this video: https://youtu.be/z2b3y_Wv93U Subsribe to Chemistry_Net: http://www.youtube.com/channel/UCRHkadk8a3zbg7RsKYwcuHw?view_as=public Relevant Videos: https://www.youtube.com/playlist?list=PLGEE3kLOMCp46vZf8gFM-p08D6dzNoBXW https://youtu.be/uJSlfl1hU_k https://youtu.be/LcA7-8755rE For theory and examples please see: Chemistry Net: http://chem-net.blogspot.com/ http://www.chem.ucla.edu/harding/tutorials/cc.pdf
Views: 2498 Chemistry_Net
2423 PE02BMC 014 - Carbocation Stability 005
 
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Arrange the following carbocations in order of increasing stability (least stable to most stable).
Reaction Intermediate(Carbanion&Its Stability)in Organic chemistry for JEE-Main | JEE-Advance
 
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Carbocations and Carbanions are some of the most important topics in General Organic Chemistry for Jee Mains & Advance. Carbocations:- Carbocations are the key intermediates in several reactions and particularly in nucleophilic substitution reactions. Structure of Carbocations : Generally, in the carbocations the positively charged carbon atom is bonded to three other atoms and has no nonbonding electrons. It is sp2 hybridized with a planar structure and bond angles of about 120°. There is a vacant unhybridized p orbital which in the case of CH3+ lies perpendicular to the plane of C—H bonds. Stability of Carbocations: There is an increase in carbocation stability with additional alkyl substitution. Thus one finds that addition of HX to three typical olefins decreases in the order (CH3)2C=CH2 greater CH3—CH = CH2 greater CH2 = CH2. This is due to the relative stabilities of the carbocations formed in the rate determining step which in turn follows from the fact that the stability is increased by the electron releasing methyl group (+I), three such groups being more effective than two, and two more effective than one. Stability of carbocations 3°greater 2° greater 1° greater CH3+ Electron release : Disperses charge, stabilizes ion. Further, any structural feature which tends to reduce the electron deficiency at the tricoordinate carbon stabilizes the carbocation. Thus when the positive carbon is in conjugation with a double bond, the stability is more. This is so, because due to resonance the positive charge is spread over two atoms instead of being concentrated on only one. This explains the stability associated with the allylic cation. The benzylic cations are stable, since one can draw canonical forms as for allylic cations. The benzyl cation stability is affected by the presence of substituents on the ring. Electron donating p-methoxy and p-amino groups stabilize the carbocation by 14 and 26 kcal/mole, respectively. The electron withdrawing groups like p-nitro destabilize by 20 kcal/mol. A hetero atom with an unshared pair of electrons when present adjacent to the cationic centre strongly stabilizes the carbocation. The methoxymethyl cation has been obtained as a stable solid CH3O+CH2SbF6-. Cyclopropylmethyl cations are even more stable than the benzyl cations. This special stability is a result of conjugation between the bent orbitals of the cyclopropyl ring and the vacant p orbital of the cationic carbon. That the carbocations are planar is shown by the fact that these are difficult or impossible to form at bridgeheads, where they cannot be planar. The stability order of carbocation is explained by hyperconjugation. In vinyl cations (CH2 = C+H), resonance stability lacks completely and these therefore are very much less stable. Carbanions Structure of Carbanions: A carbanion possesses an unshared pair of electron and thus represents a base. The best likely description is that the central carbon atom is sp3 hybridized with the unshared pair occupying one apex of the tetrahedron. Carbanions would thus have pyramidal structures similar to those of amines. It is believed that carbanions undergo a rapid interconversion between two pyramidal forms. There is evidence for the sp3 nature of the central carbon and for its tetrahedral structure. At bridgehead a carbon does not undergo reactions in which it must be converted to a carbocation. However, the reactions which involve carbanions at such centres take place with ease, and stable bridgehead carbanions are known. In case this structure is correct and if all three R groups on a carbanions are different, the carbanion should be chiral. All reactions therefore, which involve the formation of chiral carbanion should give retention of configuration. However, this never happens and has been explained due to an umbrella effect as in amines. Thus the unshared pair and the central carbon rapidly oscillate from one side of the plane to the other. Stability and Generation of Carbanions: The Grignard reagent is the best known member of a broad class of substances, called organometallic compounds where carbon is bonded to a metal lithium, potassium sodium, zinc, mercury, lead, thallium – almost any metal known. Whatever the metal it is less electronegative than carbon, and the carbon metal bond like the one in the Grignard reagent highly polar. Although the organic group is not a full-fledged carbanion – an anion in which carbon carries negative charge, it however, has carbanion character. Or organometallic compounds can serve as a source from which carbon is readily transferred with its electrons. On treatment with a metal, in RX the direction of the original dipole moment is reversed (reverse polarization). We Hope, you all will enjoy the lecture. Thanks #RJcoaching #CarbanionItsStability #forXIXIIJEEMainJEEAdvanceNEET
Views: 65 R.J Coaching
Inductive Effect 1 I NEET/JEE
 
41:50
Helios Educore Pvt. Ltd. Sunshine Business Park, Plot - 5A, Sector-94, Noida (UP) INDIA-201301 Chemistry Video Lectures to prepare for JEE-Main, JEE-Advanced, NEET & and Board Exams. visit us : www.helioseducore.com Email : [email protected] Mob. : 08010000068 For Purchase : http://helioseducore.com/product-category/buy-book/ or Amazon Search Er Dushyant Kumar
Views: 510076 Helios Educore
Alkene stability
 
05:30
How increased substitution leads to more stable alkenes.
Understanding why carbocations shift
 
00:48
Carbocations will rearrange to an adjacent, more stable possible if possible. These have different names based on which atoms are rearranging. The Hammond-Postulate more accurately describes what transition states look like. Paraphrased version: “Transition states most closely resemble the species with the highest energy.”Watch more of this topic at ► http://bit.ly/28Jd8Gc Download this PDF: http://bit.ly/28Jd9Kq GET MORE CLUTCH! VISIT our website for more of the help you need: http://bit.ly/28JdjRR SUBSCRIBE for new videos: http://cltch.us/1axA33X --- LET'S CONNECT! Facebook: http://cltch.us/1JLgiSZ Twitter: http://cltch.us/1NLcKpu Instagram: http://cltch.us/1If5pb7 Google+: http://cltch.us/1E34o85 Clutch Prep = Textbook specific videos to help you pass your toughest science classes.
Views: 7632 Clutch Prep
Carbocation Stability || What you CANNOT find in most Books || VERY IMPORTANT for IIT JEE/ NEET
 
06:58
Carbocation stability is a very important topic for students preparing for engineering and medical entrance exams. This is because, a lot of Chemistry questions are asked from carbocation stability mechanism in IIT JEE / NEET exams. The video discusses stability reasons like hyperconjugation, resonance, lone pairs of electrons, multiple bonds, etc. Along with providing the basics, the video also covers all rules of carbocation stability, as well as, the complete chart of 16 carbocations, ranked in order of their stability. This chart can be memorised for IIT JEE / NEET, and applied as is. It is often difficult to understand which carbocations have more stability. Many books do not provide all rules of carbocation stability in one place. So here, we have compiled together EVERY rule to understand which carbocation will be more stable than the other, along with reasons. The explanation is very easy in Hindi, to help students understand this very important topic of Chemistry in a simple manner. The instructor in the video is a chemical engineer from IIT Roorkee. His explanations are extremely logical, simple and easy to understand. #chemistry #iitjee #neet #carbocationstability Visit our website: www.targetacademy.in
Organic Chemistry || GOC 03 || Resonance 02 : Stability of Resonance Structures JEE MAINS/NEET
 
30:15
To support me in my journey you can donate ([email protected] 9161123482) or Alakh Pandey ,Bank of Baroda, Rajrooppur, Allahabad,U.P IFSC: BARB0RAJROO Account No: 19210100020819 A small amount of Rs 100 even will be of great help. Follow us on: Instagram https://www.instagram.com/physicswallah/ Facebook: https://www.facebook.com/physicswallah 11 chap 12 || Organic Chemistry || GOC 01 : Inductive Effect and Acidic Strength JEE MAINS/ NEET || https://www.youtube.com/watch?v=hdAW3ng8gx0&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM Organic Chemistry || GOC 02 || Resonance 01 : How to Draw Resonance Structures IIT JEE / NEET || https://www.youtube.com/watch?v=rHMMX18a8ME&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM&index=2 Organic Chemistry || GOC 03 || Resonance 02 : Stability of Resonance Structures JEE MAINS/NEET https://www.youtube.com/watch?v=RdcC7_E8yeM&index=3&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM Organic Chemistry || GOC 04 || Resonance 03 : Mesomeric Effect Complete Topic JEE MAINS/NEET || https://www.youtube.com/watch?v=qkTYf0sHDiQ&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM&index=4 Organic Chemistry || GOC 05 : Hyperconjugation Effect in Carbocation , Free Radical JEE MAINS/NEET https://www.youtube.com/watch?v=jGyb5HCz-wU&index=5&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM Organic Chemistry || GOC 06 : Aromatic , Anti Aromatic and Non-Aromatic Compounds JEE MAINS/NEET https://www.youtube.com/watch?v=lVbuBY0YMu4&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM&index=6 Organic Chemistry || GOC 07 : CARBOCATION - Reaction Intermediate 01 JEE MAINS/NEET https://www.youtube.com/watch?v=DDYJ6piwFVU&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM&index=7 Organic Chemistry || GOC 08 : FREE RADICAL and CARBOANION - Reaction Intermediate 02 JEE MAINS/NEET https://www.youtube.com/watch?v=-dEaa1mCfps&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM&index=8 GOC 09 :CARBENE || Singlet and Triplet CARBENE- Reaction Intermediate 03 JEE MAINS/NEET https://www.youtube.com/watch?v=WsHML3uhclY&index=9&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM GOC 10 : Rearrangement of Carbocation | Hydride , Methyl and Phenyl Shifting JEE MAINS/NEET https://www.youtube.com/watch?v=_l_GOioLd2Q&index=10&list=PLF_7kfnwLFCGnyrRfiT8251OrVqJzHnBM
Understanding trends of alkene stability
 
04:29
Not all alkenes were created equal. Like carbocations, alkenes are stabilized through a phenomenon called hyperconjugation. Watch more of this topic at ► http://bit.ly/28IBmBC Download this PDF: http://bit.ly/28IBkJY GET MORE CLUTCH! VISIT our website for more of the help you need: http://bit.ly/28IBmBB SUBSCRIBE for new videos: http://cltch.us/1axA33X --- LET'S CONNECT! Facebook: http://cltch.us/1JLgiSZ Twitter: http://cltch.us/1NLcKpu Instagram: http://cltch.us/1If5pb7 Google+: http://cltch.us/1E34o85 Clutch Prep = Textbook specific videos to help you pass your toughest science classes.
Views: 8637 Clutch Prep
Stability Of Carbocations and Carbanions (Applications of Inductive effect Jee Mains & Advance
 
10:01
Carbocations and Carbanions are some of the most important topics in General Organic Chemistry for Jee Mains & Advance. Carbocations:- Carbocations are the key intermediates in several reactions and particularly in nucleophilic substitution reactions. Structure of Carbocations : Generally, in the carbocations the positively charged carbon atom is bonded to three other atoms and has no nonbonding electrons. It is sp2 hybridized with a planar structure and bond angles of about 120°. There is a vacant unhybridized p orbital which in the case of CH3+ lies perpendicular to the plane of C—H bonds. Stability of Carbocations: There is an increase in carbocation stability with additional alkyl substitution. Thus one finds that addition of HX to three typical olefins decreases in the order (CH3)2C=CH2 greater CH3—CH = CH2 greater CH2 = CH2. This is due to the relative stabilities of the carbocations formed in the rate determining step which in turn follows from the fact that the stability is increased by the electron releasing methyl group (+I), three such groups being more effective than two, and two more effective than one. Stability of carbocations 3°greater 2° greater 1° greater CH3+ Electron release : Disperses charge, stabilizes ion. Further, any structural feature which tends to reduce the electron deficiency at the tricoordinate carbon stabilizes the carbocation. Thus when the positive carbon is in conjugation with a double bond, the stability is more. This is so, because due to resonance the positive charge is spread over two atoms instead of being concentrated on only one. This explains the stability associated with the allylic cation. The benzylic cations are stable, since one can draw canonical forms as for allylic cations. The benzyl cation stability is affected by the presence of substituents on the ring. Electron donating p-methoxy and p-amino groups stabilize the carbocation by 14 and 26 kcal/mole, respectively. The electron withdrawing groups like p-nitro destabilize by 20 kcal/mol. A hetero atom with an unshared pair of electrons when present adjacent to the cationic centre strongly stabilizes the carbocation. The methoxymethyl cation has been obtained as a stable solid CH3O+CH2SbF6-. Cyclopropylmethyl cations are even more stable than the benzyl cations. This special stability is a result of conjugation between the bent orbitals of the cyclopropyl ring and the vacant p orbital of the cationic carbon. That the carbocations are planar is shown by the fact that these are difficult or impossible to form at bridgeheads, where they cannot be planar. The stability order of carbocation is explained by hyperconjugation. In vinyl cations (CH2 = C+H), resonance stability lacks completely and these therefore are very much less stable. Carbanions Structure of Carbanions: A carbanion possesses an unshared pair of electron and thus represents a base. The best likely description is that the central carbon atom is sp3 hybridized with the unshared pair occupying one apex of the tetrahedron. Carbanions would thus have pyramidal structures similar to those of amines. It is believed that carbanions undergo a rapid interconversion between two pyramidal forms. There is evidence for the sp3 nature of the central carbon and for its tetrahedral structure. At bridgehead a carbon does not undergo reactions in which it must be converted to a carbocation. However, the reactions which involve carbanions at such centres take place with ease, and stable bridgehead carbanions are known. In case this structure is correct and if all three R groups on a carbanions are different, the carbanion should be chiral. All reactions therefore, which involve the formation of chiral carbanion should give retention of configuration. However, this never happens and has been explained due to an umbrella effect as in amines. Thus the unshared pair and the central carbon rapidly oscillate from one side of the plane to the other. Stability and Generation of Carbanions: The Grignard reagent is the best known member of a broad class of substances, called organometallic compounds where carbon is bonded to a metal lithium, potassium sodium, zinc, mercury, lead, thallium – almost any metal known. Whatever the metal it is less electronegative than carbon, and the carbon metal bond like the one in the Grignard reagent highly polar. Although the organic group is not a full-fledged carbanion – an anion in which carbon carries negative charge, it however, has carbanion character. Or organometallic compounds can serve as a source from which carbon is readily transferred with its electrons. On treatment with a metal, in RX the direction of the original dipole moment is reversed (reverse polarization). We Hope, you all will enjoy the lecture. Thanks
Views: 48 R.J Coaching

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