Concept explainers
(a)
Interpretation:
A second chain propagation step in the given reaction has to be proposed.
Concept introduction:
Halogenation of
Radical chain reaction:
Initiation reaction:
Chain propagation:
Chain termination:
(b)
Interpretation:
Heat of the reaction,
Concept introduction:
Halogenation of alkanes: The replacement of one or more hydrogen atoms by halogen. When alkanes is heated or irradiated with the light of specific wavelength, the alkyl halide are formed by radical chain reaction.
Radical chain reaction:
Initiation reaction:
Chain propagation:
Chain termination:
It is a change in enthalpy of a homolysis reaction at absolute zero where a molecule is broken down into two free radicals.
(c)
Interpretation:
The energies and relative rates of the set chain propagation steps in section 8.5B with given reaction has to be compared.
Concept introduction:
Halogenation of alkanes: The replacement of one or more hydrogen atoms by halogen. When alkanes is heated or irradiated with the light of specific wavelength, the alkyl halide are formed by radical chain reaction.
Radical chain reaction:
Initiation reaction:
Chain propagation:
Chain termination:
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Organic Chemistry
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- A student adds NBS to a solution of 1-methylcyclohexene and irradiates the mixture with a sunlamp until all the NBS has reacted. After a careful distillation, the product mixture contains two major products of formula C7H11Br. (a) Draw the resonance forms of the three possible allylic free radical intermediates.arrow_forwarda) Consider the reaction of HBr with ethylene and propylene. At roomtemperature the reaction of propylene with HBr is much faster than thereaction with ethylene.Using reaction energy diagrams and your knowledge of carbocationstability explain why this is so. b) Xylene (dimethylbenzene) is a commonly used chemical in the printingindustry and as a cleaning solvent for oily waste. It is also used whenpreparing histological samples to remove waxes from biological samples.Draw the three possible structures for this compound and give the UPACnames for each. Define which structures are ortho, meta, and para.arrow_forwardThe rate of elimination of cis-1-bromo-4(1,1-dimethyl)cyclohexane is proportional to the concentration of both substrate and base, but that of the trans isomer is proportional only to the concentration of the substrate. a) draw the structures of cis and trans 1-bromo-4(1,1,-dimethyl)cyclohexane b) explain the difference in kinetics between the elimination reaction of cis and trans isomers.arrow_forward
- When piperidine undergoes the series of reactions shown here, 1,4-pentadiene is obtained as the product. When the four different methyl- substituted piperidines undergo the same series of reactions, each forms a different diene: 1,5-hexadiene; 1,4-pentadiene; 2-methyl-1,4-pentadiene; and 3-methyl-1,4-pentadiene. Which methyl-substituted piperidine forms which diene?arrow_forward)a) The radical chlorination of pentane is a poor way to prepare 1-chloropentane but radical chlorination of neopentane, (CH).C, is a good way to prepare neopentyl chloride, (CH) CCH;CI. Explain. b) Show the mechanism for the radical chlorination of neopentane. Illustrate homolytic bond cleavage and bond formation.arrow_forwardb) Explain in detail what characteristics of the alkyl halide influence whether a mechanism will be SN1 or SN2. c) Explain in detail what characteristics of a nucleophile influence whether a reaction will be SN1 or SN2.arrow_forward
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