Question

pleas help 5,6,7,8,9,10

III IV 5. The product of free-radical halogenation reactions is an alkyl halide. The major amount of this halide forms during the second step of propagation. However, you should be aware that one possible termination step also forms alkyl halides. Why does the majority of the alkyl halide product come from the propagation step and not the termination step? A. At any given time during the reaction, the concentration of both the alkyl radical and the halide radical is high enough that they can readily come together to form alkyl halides during propagation. B. At any given time during the reaction, the concentration of both the alkyl radical and the halide radical is so low that the chance of each of them finding the other to form alkyl halides during a termination step is very small. C. The initiation step converts 100% of the halogen to halide radicals through a light-or heat-induced homolytic bond cleavage. This step ensures that there is always a high concentration of halide radical present for reactivity in a propagation step D. The second step of propagation (combination of an alkyl radical with a halide radical) is highly endothermic and therefore takes place very rapidly. E. Once the alkyl halide forms during a termination step, the carbon-halogen bond is broken in a homolytic fashion and the newly generated carbon radical goes back into a propagation step for further reactivity. 1|Page 6. The most stable conformation for 1,2-ethanediol (ethylene glycol) is shown below. It is the most stable conformation because: A. this corresponds to an anti conformation. H B. in general, gauche conformations possess the minimum energy. H OH C. it is stabilized by intramolecular hydrogen bonding. D. it is a staggered conformation. E. it has the highest energy of all the possibilities. H OH н 7. Predict the major product of the following reaction. F2/hv ? Y B. D. F E. The reaction does not take place.

Answer 1

Answer 5 Correct choice is B.

Explanation :

A is incorrect because the concentration of alkyl radicals and halide is not high, rather it is low.

C is incorrect because initiation is not 100% complete. It only provides catalytic amount of radicals.

D is incorrect because second propagation step is exothermic while first is endothermic.

E is incorrect because alkyl halide does not undergoes homolytic cleavage

Answer 6 Correct choice is C

Explanation:

In given conformation, the -OH groups are in close proximity and can undergo intramolecular hydrogen bonding which stabilizes it more than anti-conformation.

A is incorrect because it is not anti conformation.

B is incorrect because gauche conformation possess more energy than anti.

D is incorrect because it is staggered but not most stable.

E is incorrect because it has lowest energy.

Answer 7 Correct choice is A

Explanation : It is because tertiary radical is most stable and flourination is preferred at tertiary carbon.

Answer 8 Correct choice is D

Explanation : It is because propagation step is that in which there is no net radical formation.

In III as well as V, there occurs propagation.

Answer 9 Correct choice is E

Explanation : It is because in E, there is generation of radical from other radical and hence, it is propagation step and not terminantion.

Answer 10 Correct choice is B

Explanation : Iodine radicals are not very reactive to cause reaction because all steps are endothermic with iodine.