Concept explainers
(a)
Interpretation:
The radicals
Concept introduction:
A process of
The minimum amount of energy needed to dissociate a bond is called the
(b)
Interpretation:
The second step of propagation of the free radical addition is energetically unfavorable is to be justified.
Concept introduction:
A process of polymerization in which the growth of chain involves free radicals is called free radical polymerization. The process includes three steps; the chain initiation step, the chain propagation step and the chain termination step.
The minimum amount of energy needed to dissociate a bond is called the bond dissociation energy. The term bond dissociation energy is only used for diatomic species. The covalent bonds have low value of bond dissociation energy.
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Organic Chemistry
- Alkyl halides can be reduced to alkanes by a radical reaction with tributyltin hydride, (C4H9)3SnH, in the presence of light (hv). Propose a radical chain mechanism by which the reaction might occur. The initiation step is the light-induced homolytic cleavage of the Sn-H bond to yield a tributyltin radical.arrow_forwardWrite the reagent or draw structures of the starting material or organic product(s) in the following reactions. If more than one product is formed, identify the major product where possible. (a) (b) HO OH OH H2SO4 ? Cl₂ ? FeCl3arrow_forwardWhen HBr adds to (CH3)2C = CH2 under radical conditions, two radicals are possible products in the first step of chain propagation. Draw the structure of both radicals and indicate which one is formed. Then draw the preferred product from HBr addition under radical conditions.arrow_forward
- Chlorination of 2-butanone yields two isomeric products, each having the molecular formula C4H7ClO. (a) What are these two compounds? (b) Write structural formulas for the enol intermediates that lead to each of these compounds. (c) Using curved arrows, show the flow of electrons in the reaction of each of the enols with Cl2.arrow_forward2-chloropropane is a major product of the reaction of chlorine with propane under ultraviolet light. Write the mechanism for this reaction including the initiation step and the two propagation steps.arrow_forwardPropylene does not undergo free radical polymerization readily because there are two competing steps after initiation: propagation and hydrogen atom abstraction.(a) Using a generic radical R• as a reactant with propylene, draw the mechanism and products for the two competing steps.(b) Which step produces the more stable product?(c) How do your results explain propylene’s poor reactivity in free radical polymerization?arrow_forward
- Write the propagation steps leading to the formation of dichloromethane (CH2Cl2) from chloromethanearrow_forward(a) Draw the two isomeric dienes formed when CH2 = CHCH2CH(Cl)CH(CH3)2 is treated with an alkoxide base, (b) Explain why the major product formed in this reaction does not contain the more highly substituted alkene.arrow_forwardExplain why the bond dissociation enthalpy of a C-H bond in benzene is significantly greater than that in alkanesarrow_forward
- The rate law for addition of Br2 to an alkene is first order in Br2 and first order in the alkene. Does this information suggest that the mechanism of addition of Br2 to an alkene proceeds in the same manner as for addition of HBr? Explain.arrow_forward21.) Calculate the enthalpy of hydrogenation of benzene to cyclohexane from the following reactions A,H (kJ/mol) C6H6 (1) + 15/2 02 (g) → 6 CO2 (g) + 3 H20 (1) C6H12 (1) + 9 02 (g) → 6 CO2 (g) + 6 H20 (1) H2 (g) + ½ 02 (g) → H2O (1) -3268 -3920 -285.83 a.) -205 kJ/mol b.) -1507 kJ/mol c.) -938 kJ/mol d.) -366 kJ/molarrow_forwardThere are two alkenes that react with HBr to give 1-bromo-1-methylcyclohexane. Draw their structures.arrow_forward
- Organic ChemistryChemistryISBN:9781305580350Author:William H. Brown, Brent L. Iverson, Eric Anslyn, Christopher S. FootePublisher:Cengage Learning