Question

Which of the following produces the most stable carbocation?

allyl bromide

2-bromo-2-methylpropane

bromobenzene

benzyl bromide

Answer 1

tertiary carbocation-------provides most stable

Which of the following produces the most stable carbocation?

allyl bromide--------answer

2-bromo-2-methylpropane

bromobenzene

benzyl bromide

-----------------------

carbocation

The charged carbon particle in a carbocation is a "sextet", i.e. it has just six electrons in its external valence shell rather than the eight valence electrons that guarantees most extreme steadiness (octet run the show). In this manner, carbocations are frequently responsive, trying to fill the octet of valence electrons and also recover a nonpartisan charge. One could sensibly accept a carbocation to have sp3 hybridization with a discharge sp3 orbital giving positive charge. Be that as it may, the reactivity of a carbocation all the more nearly looks like sp2 hybridization with a trigonal planar atomic geometry. A case is the methyl cation, CH+3 Request of security of cases of tertiary (III), optional (II), and essential (I) alkylcarbenium particles, and additionally the methyl cation (far right).

Carbocations are regularly the objective of nucleophilic assault by nucleophiles like hydroxide (OH−) particles or halogen ionsarbocations normally experience improvement responses from less steady structures to similarly steady or more steady ones with rate constants in abundance of 109 s−1. This reality muddles manufactured pathways to many mixes. For instance, when 3-pentanol is warmed with fluid HCl, the at first framed 3-pentyl carbocation revises to a measurable blend of the 3-pentyl and 2-pentyl. These cations respond with chloride particle to deliver about 1⁄3 3-chloropentane and 2⁄3 2-chloropentane.

A carbocation might be balanced out by reverberation by a carbon-carbon twofold bond by the ionized carbon. Such cations as allyl cation CH2=CH–CH2+ and benzyl cation C6H5–CH2+ are more steady than most different carbocations. Atoms that can shape allyl or benzyl carbocations are particularly responsive. These carbocations where the C+ is contiguous another carbon particle that has a twofold or triple bond have additional solidness in view of the cover of the vacant p orbital of the carbocation with the p orbitals of the π bond. This cover of the orbitals permits the charge to be shared between numerous particles – delocalization of the charge - and, along these lines, settles the carbocation. Hyperconjugation is likewise a balancing out variable for carbocations. The vacant pi orbitals of the carbon iota acknowledges a couple of electrons from the alpha carbon which then gets the positive charge. More alpha hydrogens expands the dependability of carbocation. Soundness arrange additionally takes after sp3 > sp2 > sp hybridization of the carbon iota bearing positive charge.