9. By employing our understanding of nucleophiles and electrophiles, as well as kinetics and thermodynamics, we should be able to predict the electron-pushing arrow mechanisms, and the corresponding products, for reactions that we have not explicitly discussed in class. An example of this is the two-step addition of a hydrohalic acid (HX) across a pi bond, wherein the pi bond behaves as a the electron donor. However, as shown in the example below, there often exists the possibility of obtaining more than one product: H-Br Br A Br Br a. Using the pi bond between carbons 1 & 2 as the donor electrons, draw complete electron-pushing arrow mechanisms that account for the formation of each product (a-c) above. It is advisable for you to count your atoms in both the stating material and products. b. The formation of which product(s) above is kinetically favored? How do you know? c. The formation of which product(s) above is thermodynamically favored? How do you know? d. Sketch a Gibbs Free Energy Diagram that reflects your answers from parts (b) & (c).

“Since you have posted a question with multiple sub-parts, we will solve first three subparts for you. To get remaining sub-part solved please repost the complete question andmention the sub-parts to be solved.” In electron pushing mechanism the arrow is starting from electron donor species to electron receiver species. A product which forms faster is the kinetic product and the product which more stable is the thermodynamically favored product. Electron donor double bond donates electrons to electron deficient H atom to form a carbocation. In second step nucleophile attack at carbocation (electrophile) to form the given product A - C. The complete mechanism is as shown below, Formation of product A follows Markovanikov rule through most stable carbocation (tertiary carbocation) to form 1,2-addition product. The above reaction followed 1-4 addition to form the given product B. The above product C formed through anti-Markovnikov rule that is 1,2- addition product. Commonly in above reaction 1,2- addition product and 1,4- addition product are formed. The 1,2- addition product with stable carbocation is more stable. More substituted alkenes are more stable than least substituted alkene. From given three product B is the more substituted alkene (trisubstituted alkene). Less substituted alkene is less stable and thus it is kinetically favored product. In the given reaction Product A and C both are disubstituted alkene, product A form through stable cation (tertiary cation) and product C form through primary cation that is less stable cation. Thus, 1,2 addition product with less stable carbocation intermediate is a kinetically favored (least stable) product. Answer: Product C is the kinetically favored product.The most stable product in the reaction is the thermodynamically favored product. Here, product B is most stable among three that is trisubstituted alkene. Thus, it is thermodynamically favored product. Answer: Product B