Which one of the following alcohols undergoes dehydration at the fastest rate on

ID: 902195 • Letter: W

Question

Which one of the following alcohols undergoes dehydration at the fastest rate on being heated with sulfuric acid?

1-Pentanol

2-Pentanol

3-Pentanol

Cyclopentanol

1-Methylcyclopentanol

3-Ethyl-4-methyl-1-heptene

3-Ethyl-4-propyl-1-pentene

3-Ethyl-4-methyl-1-octene

3-Ethyl-2-propyl-4-pentene

Which one of the following statements does not correctly describe E2 (bimolecular elimination) reactions of alkyl bromides?

The rate of an E2 reaction depends on the concentration of the alkyl bromide.

The rate of an E2 reaction depends on the concentration of the base.

Both the C—H bond and the C—Br bond are broken in the same step.

Carbocations are intermediates in E2 reactions.

1-Pentanol

2-Pentanol

3-Pentanol

Cyclopentanol

1-Methylcyclopentanol

CH CH2 CHCHCH CHjCH2 CH2CH2CH3

Choose 1-Methylcyclopentanol since this is the most "outside" Alcohol and is attached to a tertiary carbon, making it easy to strip it!.

since the Alcohol is in the far left/right, therefore H2SO4 molecules can "attack" faster and the -OH group can leave/exit the molecule faster

Choose the longest chain including the double bond... count from top to bottom

I count 7 carbons, therefore this will be an heptene

in the 3 carbon - ethyl

4 - methyl

Now, its time to name it:

3-ethyl-4-methyl-1-heptene

NOTE that you could have guessed since there is only one heptene option

Some notes on E2:

The mechanism by which it occurs is a single step concerted reaction with one transition state

The rate at which this mechanism occurs is second order kinetics, and depends on both the base and alkyl halide

Therefore, the only option that does not suit E2 is "d" thre are no intermediates since this is a single step!

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