Question

(i) The reaction above is purposed to occur in 3 steps. From thelist select the mechanism description that is associated with theindicated step (assume all steps are in the forward direction).

(a) The alkyloxonium ionis protonated as the bromide ion is formed.
(b) The bromide ion attacks thecarbocation.
(c) The alcoholic oxygen attacks thecarbocation.
(d) The alcoholic oxygen is protonated as thebromide ion is formed.
(e) A water molecule attacks thecarbocation.
(f) A water molecule is formed at the sametime the carbocation is formed.
(g) A water molecule is formed at the sametime the alkyloxonium ion is formed.

Step 1 ---Select---bgdceaf

Step 2 ---Select---gcbdfae

Step 3 ---Select---cefbagd

(ii) Which letter from the ones you selected above corresponds tothe mechanism step in which

Only a covalent bondis being transformed into a lone pair.
Only a lone pair isbeing transformed into a covalent bond.
Both a lone pair isbeing transformed into a covalent bond and a covalent bond is beingtransformed into a lone pair.

(iii) Which of the following is thenucleophile in step 3?
---Select---carbocationalcohol moleculebromide ionalkyoxonium ionhydrogen bromide moleculewater molecule
(iv) Which step in the reaction mechanism is a Bronsted acid-base reaction?
---Select---123
Which step in the reaction mechanism is aLewis acid-base reaction, (but not a Bronsted acid-basereaction?)
---Select---321
Which step in the reaction mechanism is unimolecular?
---Select---321

Answer 1

This is the SN1 Reaction, these questions are pretty repetitive youjust have to go through it step by step and look for eachthing:

Step 1: the alcoholic oxygen is protonated as the bromide ion isformed (D)
Step 2: a water molecule is formed at the same time the carbocationis formed (F)
Step 3: the bromide ion attacks the carbocation (B)

F Only a covalent bond is beingtransformed into a lone pair.
B Only alone pair is being transformed into a covalent bond.
D Both alone pair is being transformed into a covalent bond and a covalentbond is being transformed into a lone pair.

The Bromide Ion is the nucleophile instep 3


Which step in the reactionmechanism is a Bronsted acid-basereaction?
1


Which step in thereaction mechanism is a Lewis acid-base reaction, (butnot a Bronsted acid-base reaction?)
3

Which step in thereaction mechanism is unimolecular?
2

Answer 2

The nucleophile is the Bromide Ion