14.7 Types Of Organic Reaction And Reaction Mechanics Flashcards
What is reaction mechanism
The series of steps that take place in the course of the overall reactions
What are the two ways in which covalent bonds can break
Homolytic fission and heterolytic fission
What is homolytic fission
In this type of bond breaking, both the atoms at each end of the bond leave with one electron from the pair that formed the covalent bond
The species produced when a bond breaks homolytically is called
Free radicals
Reaction of HCl breaking homolytically
HCl—>H•+Cl•
All free radicals
Have an unpaired electron and are very reactive
The tree steps in a free radical reaction are
Initiation step: the formation of free radicals to start a reaction off
Propagation step: steps in a mechanism that regenerates more free radicals (the radicals formed can then attack reactant molecules to form more free radicals
Termination step: when two free radicals meet and form a product molecule
What is heterolytic fission
In heterolytic fission, the more electronegative atom takes both electrons in the covalent bond
The equation of heterolytic fission
H-Cl —> H+ + Cl-
(A small arrow from the hydrogen bond to the chlorine in reactant side shows the movement of pair of electrons
What is carbocation
An alkyl group with a single positive charge on one of its carbon atoms.
What is inductive effect
The uneven sharing of electrons along a covalent bond.
What species have an inductive effect
Electron donating species have a positive inductive effect while electron withdrawing species gas a negative inductive effect
What are the three types of carbocation
Primary carbocation(least stable)- one alkyl group and two hydrogens
Secondary carbocation- two alkyl groups and one hydrogen
Tertiary carbocation(most stable)- three alkyl groups
Any alkyl group attached to positively charged carbon atom tend to be
Electron donating
What effect does alkyl group pushing electrons away from themselves have
It reduces the charge density of positive charge on carbocation. This has the effect of spreading out the charge around the carbocation making it energetically more stable.
