Question

1. Why do you think alkenes would rather undergo catalytic hydrogenation by syn addition rather than anti addition? Support your answer with an example. (4 pts) 2. What does the word stereoselectivity mean and how does it apply to the catalytic hydrogenation of alkenes? (2 pts) 3. What is the correlation between the heat of hydrogenation of an alkene and its degree of substitution? (2 pts)

Answer 1

t. In hydrogenation Reaction Reagent used Here. He are adsorption in Suface at first. Then hydrogenation take placed, H... H2 Ni. Nifty Ni reaction add sorption adsorptim dicha 1/ / / CH2=CH2 - Ni He C - CH2 CH₂ - CH3. CH₂ - c S7 Til I it only possible in Syn addition Reaction. Therefore aluenes would rather undergo catalytic hydrogenation by addition rather than Anti addition © stereo selectivity: sted stereo selectivity nothing but a property of chemical reaction. where reactant (single) molecule form products of mixture of otoren unequat stereo isomer.

HD of sodo stereo selectivity on Hydrogenehan of Hjkето , CH3 CH3 HB CH H Anti [Br & H are opposite sides) | Br & Н оте same sides) (major) 3. (minor) The stability of alkene is determine by calculating the amount of energy associated bydrogenation of the molecules o As tragen Hydrogenation process is double bond breat proceds then in this process the ener released is proportional to the energy in energy in double bond of the molecules. Nou ecules. Now degree of substitution is nothing but a c=6' so, if degree of substitution increases then heat of hydrogenation also increases. alena