CH3 CH3 Br Br2 CH3 CH2CI2 CH3 H3C H3C Br Electrophilic addition of bromine, Br2, to alkenes yields a 1,2-dibromoalkane. The reaction proceeds through a cyclic intermediate known as a bromonium ion. The reaction occurs in an anhydrous solvent such as CH2C12. In the second step of the reaction, bromide is the nucleophile and attacks at one of the carbons of the bromonium ion to yield the product. Due to steric clashes, the bromide ion always attacks the carbon from the opposite face of the bromonium ion so that a product with anti stereochemistry is formed. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions CH3 CH3 Br CH3 .CH3 H3C H3C ig:

Suppose you were told that each reaction  is a substitution reaction, but you were not told the mechanism. Describe how you could conclude from the structure of the haloalkane or cycloalkene, the nucleophile, and the solvent that each reaction is an SN1 reaction.

Tell which of these transformations are oxidations and which are reductions based on whether there is addition or removal of O or H.

Suppose you were told that each reaction  is a substitution reaction, but you were not told the mechanism. Describe how you could conclude from the structure of the haloalkane or cycloalkene, the nucleophile, and the solvent that each reaction is an SN1 reaction.

10. Choose the major organic product of the reaction. A | В II IV Br Br Br Br Br Br2 Br Br 100°C Br IV =

Draw curved arrows to show the movement of electrons in this step of the mechanism.

Draw the energy diagram of the following reaction (label and draw reactants, intermediates, and products). Label transition state of the rate limiting step and draw the transition state of the rate determining step. Is it a concerted or stepwise reaction? Write the rate law for this reaction. How do we increase the reaction rate? If we use deutrium-tert-butyl bromide such as (CD3)3CBr instead of (CH3)3CBr, will it increase or decrease the reaction rate? Or there is no meaningful rate change. Write reasons for your answer. Draw mechanisms for reactions by drawing arrows and intermediates.

Consider the mechanism for the given nucleophilic substitution reaction. X 2H₂0

Write the expected substitution product(s) for each reaction and predict the mechanism by which each product is formed.

Consider the reaction of NaCl with 2- bromo-2-methylhexane in acetone/water. Predict the change in rate if the concentrations of both the 2-bromo-2- methylhexane and the NaCl are doubled. A) The reaction rate stays the same. B) The reaction rate doubles. C) The reaction rate is halved. D) The reaction rate quadruples E) The reaction rate triples.