Question

4. Under the right conditions, alkyl halides can undergo a reaction known as nucleophilic substitution. Two different examples of this reaction are shown below 44 Reaction! Reaction OW w NaOHD VÖLHO OH a. For both reaction and reaction II, acetone is used as a solvent (it does not participate in the reaction). Imagine that each reaction is run twice, using double the solvent volume the second time each reaction is run. You notice that when the solvent volume is doubled, the initial rate of reaction I drops to one quarter of its original rate, while the initial rate of reaction only drops to one half its original rate. Explain this observation. As part of you answer, draw an appropriately labeled reaction coordinate diagram for each reaction and circle the portion of the diagram that is key to your answer. (24 points) 24 The solution produced by the redction is optically active, while reaction of B with sodrum lodide is optically inactive. Explain these observations you do not have to describe how optical activity is measuredl. 120 points) 20

Answer 1

Solution - 2: In reaction 1, only one product is formed having inverted configuration from that of reactant configuration. So, this will rotate the polarized light in opposite direction. But in reaction 2, two enantiomers called racemic mixture are formed. These will rotate the plane polarized light into equal and opposite direction. Thereafter cancels each other's effect. Thats why this mixture is optically inactive.

solution : (a) NaOH, Acetone OH -cl Reaction I Dive TOH HO HO lace which Reaction In Reaction - I leads to the product. sua reaction formation of is invested configura configuration nverted tie sontel Inceession in Configuration Transition state In Reaction -II, place. SN' • It reaction occurs in is a taking step Est step i formation of slowest 4 is called rate carbocation is determining step. ve ch AOH side Battack Back Enantio .mes ViiuOHA front sid attack Coordinate diagram: Reaction - I Reaction - I ht 2460 son onésgy Energy Energy بیا Tod der Products Sta Pogress of -Progress of a reaction jeaction