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2023-2024 > Quiz 6-9 + Worksheets > Flashcards

Quiz 6-9 + Worksheets Flashcards

1
Q

The larger the number of Pkb, the ______ the _____ (base/acid).

A

Weaker; base

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2
Q

Is CH3 a deactivator/activator?

A

Activator

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3
Q

Electron withdrawing groups are mostly ___________ (deactivators/activators).

A

deactivators

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4
Q

List some deactivators.

A

CN (triple bond)
NO2
SO3H
C=OH … carbonyls
N+R3
Halogens

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5
Q

How to find Pkb from Pka?

A

Subtract Pka value from 14.

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6
Q

Is 1,3,5-trihexene aromatic, non aromatic or anti aromatic? Why?

A

Non aromatic because it is not cyclic.

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7
Q

A deactivator as a substituent on a benzene reacting with Br2, FeBr3 produces what major product?

A

An addition of Br on the meta position of the substituent.

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8
Q

What kind of director is NH2?

A

Ortho/para-director.

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9
Q

Why is sulfuric acid used in aromatic nitration?

A

Because of the tert-butyl cation.

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10
Q

What kind of director is OCH3?

A

Para/ortho-director…activator

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11
Q

What kind of director is OH?

A

Para/ortho director…activator.

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12
Q

What kind of director are amines?

A

Para/ortho-director…activator.

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13
Q

Is -NHC=OCH3 a meta directing group?

A

No, because it is part of the amine group.

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14
Q

Which has a UV absorption band at the longest wavelength between a conjugated cyclic and conjugated non-cyclic compound?

A

Cyclic compound.

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15
Q

Can isolated alkenes undergo Diels-Alder reactions?

A

No.

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16
Q

A diene with a OCH3 substituent on the 2nd position and a dienophile with a CHO substituent produces what kind of product?

A

A 1,4-product.

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17
Q

The carbon-carbon bonds in benzene are…

A

of equal length and intermediate between a double bond and a single bond.

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18
Q

How many pi-bonding MOs are in benzene?

A

3

19
Q

What is the difference between the modern Kekule structures and the original Kekule structures?

A

The C-C bond lengths in the modern structures are all the same and the modern structures are two resonance structures.

20
Q

Which reaction do benzene tends to undergo?

A

Substitution rather than addition reactions.

21
Q

What are non-bonding orbitals?

A

The HOMO and the LUMO MOs.

22
Q

What are the non-bonding MOs of cyclobutadiene?

A

p2 and p3.

23
Q

Which of the following concepts are used to describe the structure of benzene?
Unsaturation
Harmonic aromatization
Saturation
Resonance

A

Resonance

24
Q

Another name for cyclobutadiene is…

A

[4]annulene

25
Q

Is a not basic N (in a cyclic compound) strong or weak base?

A

Weak base.

26
Q

NH is _____ while N is ______.

A

not basic; basic

27
Q

Does conjugation increases acidity?

A

Yes.

28
Q

An ethene substituent added to a benzene is called…

A

Styrene

29
Q

Describe napthalene’s structure.

A

2 benzenes together.

30
Q

A cyclopentane substituent attached to a benzene is called…

A

Cyclopentylbenzene
or
phenylcyclopentane

31
Q

What is the electrophile in the bromination of benzene?

A

Br+

32
Q

A carbocation at a tertiary carbon is _______ (stable/not stable).

A

Not stable.

33
Q

When toulene reacts with Br2, why does it not go through addition to form a vicinal dihalide?

A

It is highly unfavorable because it would result in a nonaromatic product.

34
Q

Name one major difference between the aromatic and antiaromatic compounds.

A

Only aromatic compounds follow Huckle’s Rule.

35
Q

Based on Hammond’s Postulate, if the carbocation intermediate is antiaromatic, what can you expect from the reaction?

A

The activation energy needed to produce the intermediate would be very high.

36
Q

Why is pyrrole a much weaker base than pyridine?

A

When pyrrole is protonated, the system’s aromaticity is destroyed.

37
Q

Name C3N2H4.

A

Imidazole.

38
Q

Describe or draw imidazole compound.

A

C3N2H4 (two double bonds)

39
Q

As conjugation ___________, the HOMO-LUMO energy gap becomes _________, and the wavelength of light absorbed becomes __________.

A

increases; smaller/narrow; longer

40
Q

What does degenerate mean?

A

“Have the same energy”.

41
Q

How many degenerate bonding MOs does benzene have?

A

2 (pi 2 and pi 3)

42
Q

Antiaromatic compounds are ________, fully _____________, making them highly _________, similar to a ________ (cation/anion/radical).

A

unstable; conjugated; reactive; radical

43
Q

Deactivator __________ (decreases/increases) the rate of reactivity toward electrophilic aromatic substitution.

A

decreases

44
Q

Rank in order of stability. Least to greatest.
Cumulative
Conjugated
Isolated

A

Cummulated < Isolated < Conjugated

2023-2024 (18 decks)

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