ENDTERM

Question 1

An ion with (+) charged carbon atom.

Answer 1

Carbocation

Question 2

A Russian chemist who proposed Markovnikov’s Rule.

Answer 2

Vladimir Markovnikov

Question 3

In this rule, H attaches to the carbon with fewer alkyl substituents while X attaches to the carbon atom with more alkyl substituents.

Answer 3

Markovnikov’s Rule

Question 4

What reagents are used to yield HI in the electrophilic addition of HX to alkenes?

Answer 4

KI / H3PO4

Question 5

Why does Markovnikov’s Rule occur?

Answer 5

Stability of carbocations due to hyperconjugation and inductive effects of alkyl group. The pathway leading to the more stable carbocation has a lower activation energy, making it kinetically preferred

Question 6

In Huckel Rule, what’s the formula used to calculate the number of pi electrons?

Answer 6

2 x #of double bonds

Question 7

If the value of n is integer in the Huckel Rule, is the compound aromatic or not?

Answer 7

Aromatic

Question 8

Why do we generate HI from KI and H3PO4 in the electrophilic addition of HX to alkenes, when we can just use pure HI?

Answer 8

pure HI is unstable and prone to oxidation.

Question 9

One product forms when two are possible.

Answer 9

Regiospecific

Question 10

A process called ________ is the addition of halogens to alkenes that yields _________.

Answer 10

Halogenation, 1,2-Dihaloalkenes

Question 11

In cycloalkene halogenation, what is/are the configuration of the product/s.

Cis, Trans, or mixture?

Answer 11

Only trans-1,2-dihalocyclopentane. Reactions occurs with anti-stereochemistry.

Question 12

Uses H2O2 to oxidize Br- and Cl- to a biological equivalent of Br+ and Cl+ during cycloalkene halogenation.

Answer 12

Haloperoxides

Question 13

The process of adding of H2 to C=C in presence of metal catalyst to yield alkane.

Answer 13

Hydrogenation

Question 14

Addition of hydrogen or removal of oxygen from a molecule.

Answer 14

Reduction

Question 15

The relative stability of intermediate is related to an equilibrium constant.

True or False?

Answer 15

True

Question 16

Define Hammond Postulate

Answer 16

states that the structure of a transition state in a reaction resembles the species (reactants or products) to which it is closer in energy.

Question 17

Addition of water to alkenes to yield alcohol is what we call __________.

Answer 17

Hydration

Question 18

Hydration reactions occurs in an aqueous acidic environment. What catalyst is used in this process?

Answer 18

H2SO4 or H3PO4

Question 19

In most alkene hydrogenations, what metal catalyst and solvent is used?

Answer 19

Palladium metal / Platinum as PtO2, Acetic Acid (CH3CO2H)

Question 20

Define hydroboration.

Answer 20

Addition of B-H bond / BH3 to alkene to yield an organoborane intermediate.

Question 21

Is hydrogenation an heterogeneous or homogeneous process?

Answer 21

Heterogeneous as reactants and catalyst exist in different phases during the process. Hydrogenation occurs on the surface of solid catalyst.

Question 22

Hydrogenation occurs with syn stereochemistry. Both H add to the double bond from the same side.

True or False?

Answer 22

True

Question 23

Reaction of alkene with either Br2 or Cl2 in the presence of water.

Answer 23

Halohydrin formation

Question 24

Few alkenes are soluble in water, so bromohydric formation is often carried out in a solvent called Dimethyl sulfoxide (DMSO).

True or False?

Answer 24

True.

Question 25

Since pure Br2 is not easy to handle during bromohydrin formation, what reagent is used as a source of Br2?

Answer 25

N-Bromosuccinimide (NBS)

Question 26

What are the reagents used in Halohydrin formation from alkenes?

Answer 26

NBS - source of Br2 DMSO - Dimethyl Sulfoxide (solvent)

Question 27

Reagents used in Oxymercuration-Demercuration.

Answer 27

1. Hg(OAc)2 H2O 2. NaBH4

Question 28

Intermediate organomercury in demercuration is treated with what reagent

Answer 28

Sodium Borobydride (NaBH4)

Question 29

attachment of -OH group in oxymer-demer, follows what rule?

Answer 29

Markovnikov’s Rule. -OH in most substituted Carbon atom.

Question 30

BH3 to alkene in hydration hydroboration. syn addition or anti addition?

Answer 30

syn addition H and BH2. Non markov.

Question 31

What are the reagents used in Hydroboration?

Answer 31

1. BH3 / THF solvent 2. H2O2, OH

Question 32

Since Hydroboration follows anti-markovnikov regioselectivity, where does the OH group bonds?

Answer 32

least substituted carbon atom

Question 33

Reagents used in halogenation of alkenes.

Answer 33

X2 / CH2Cl2

Question 34

A reaction that results in a loss pf electron density for carbon due to the bond formation between carbon and other more electronegative atom.

Answer 34

Oxidation

Question 35

Oxidation: ___________ Reduction: ___________

Answer 35

adds oxygen/nitrogen, adds hydrogen

Question 36

Alkenes are oxidized to give ________.

Answer 36

epoxides

Question 37

A cyclic ether with oxygen atom in a three-membered ring.

Answer 37

Epoxide

Question 38

Epoxide is also known as

Answer 38

oxirane

Question 39

Alkenes are oxidized to give epoxides by reacting it with peroxyacid such as _________.

Answer 39

meta-chloroperoxybenzoic acid

Question 40

Peroxyacids transfer an _______ to alkene with _________-stereochemistry C-O bonds form in the ______ face of _______ bond.

Answer 40

oxygen, syn, same, double

Question 41

Epoxides undergo an acid-catalyzed ring-opening reaction with water called _______, to yield 1,2-dialcohol or diol.

Answer 41

Hydrolysis

Question 42

Addition of an -OH group.

Answer 42

Hydroxylation

Question 43

Epoxides undergo hydrolysis to yield what?

Answer 43

1,2-dialcohol or diols

Question 44

By treating the alkene with _________, hydroxylation can be carried our with going through an intermediate epoxide.

Answer 44

Osmium tetroxide (OsO4)

Question 45

1,2-dialcohol or diol is also known as

Answer 45

glycol

Question 46

Most useful double-bond cleavage reagent

Answer 46

Ozone (O3)

Question 47

Oxidation of alkenes with ozone involves passing a stream of pxygen through ________ -voltage electrical discharge.

Answer 47

high

Question 48

Ozone adds to C=C at low or high temp yielding a cyclic intermediate ________.

Answer 48

low temp, molozonide

Question 49

In oxidation of alkenes using ozone, molozonide rerranges to ________?

Answer 49

Ozonide

Question 50

Reagents used in oxidative cleavage involving ozone.

Answer 50

1. Ozone 2. Zn, CH3COOH

Question 51

In oxidative cleavage reaction using KMnO4, the solution is acidic or basic? What are the reagents used?

Answer 51

Acidic, 1. KMnO4, H3O+

Question 52

In hydroxilation by acid-catalyzed epoxide hydrolysis, what does occurs? Anti-chemistry or syn chemistry?

Answer 52

anti-chemistry

Question 53

In hydroxilation by acid-catalyzed epoxide hydrolysis, whats the yielded product?

Answer 53

1,2-dialcohol or diol. (ANTI CHEMISTRY)

Question 54

In hydroxilation by acid-catalyzed epoxide hydrolysis you starts with epoxide, what reagent is used to yield the trans-1,2-dialcohol product?

Answer 54

H3O+

Question 55

is carbene electrophilic or nucleophilic?

Answer 55

Electrophilic, as they lack electron

Question 56

A method for preparing nonhalogenated cyclopropanes.

Answer 56

Simmons-Smith reaction

Question 57

reagents used in simmons-smith reaction

Answer 57

Ch2I2 + Zn(Cu)/Ether

Question 58

Also knowns as optical isomer. One of a pair of a molecular entities which are mirror images of each other and non-superposable.

Answer 58

Enantiomer

Question 59

A mixture of equal amounts of two enantiomers.

Answer 59

Racemic mixture

Question 60

Ability of substance to rotate the plane of polarized light.

Answer 60

Optical activity

Question 61

Two halogen stoms are attached to adjacent carbon atoms in a molecule.

Answer 61

Vicinal Dihalide

Question 62

What reagents are used in dehydration of vicinal dihalides. (1,2-Dihaloalkane)

Answer 62

2KOH, ethanol

Question 63

What reagents are used to prepare alkynes by elimination of HX from alkyl halides(Haloalkene)

Answer 63

KOH, ethanol

Question 64

Bond length of C (triple bond) C

Answer 64

120 pm (shortest and strongest know C-C bond)

Question 65

A triple bond contains 2 sp2-hybridized. True or False?

Answer 65

False. 2 sp-hybridized carbon.

Question 66

What reagents are used in alkylation of acetylide anions?

Answer 66

1. NaNH2 2. RCH2Br

Question 67

Reagents used in addition of HCl and HBr (alkynes)

Answer 67

1. 2HX 2. 2Ether

Question 68

Reagents used in addition of Cl2 and Br2 (alkynes)

Answer 68

1. 2 X2 2. 2 CH2Cl2

Question 69

Do alkynes react directly with aqueous acid? Why?

Answer 69

No. Because the triple bond of alkynes are less nucleophilic than the double bond in alkenes.

Question 70

Alkynes don’t react directly with aqueous acid but can undergo hydration in the presence of what reagent?

Answer 70

Mercury (II) Sulfate

Question 71

What intermediate is formed in hydration of alkynes using mercury(II)?

Answer 71

an enol - a compound with an -OH group attached to a double bond

Question 72

Mercury (II) - Catalyzed Hydration of Alkynes occurs with _________ regiochemistry. So that, -OH group adds to the more substituted carbon.

Answer 72

Markovnikov

Question 73

Reagents used in Mercury (II) - Catalyzed Hydration of Alkynes

Answer 73

1. H2O, H2SO4 2. HgSO4

Question 74

Two isomers that undergo spontaneous interconversion accompanied by the change in position of hydrogen.

Answer 74

Tautomers

Question 75

A process where enol intermediate in Mercury (II) Catalyzed Hydration rearranges into ketone.

Answer 75

Keto-enol tautomerism

Question 76

Why enol intermediate rearranges into ketone by a process called keto-enol tautomerism?

Answer 76

Since enols are unstable, they spontaneously tautomerize into a ketone (Markovnikov product).

Question 77

An Internal Alkyne

Answer 77

It is where a triple bond is located between two carbon atoms within the carbon chain. Neither of the carbon is directly bonded to H.

Question 78

How alkynes are reduced to alkene?

Answer 78

By addition of H2 with metal catalyst

Question 79

What catalyst is used for complete reduction of alkyne to alkane?

Answer 79

Palladium on C (Pd/C)

Question 80

Why use Lindlar catalyst in reduction of alkynes?

Answer 80

Hydrogenation at the alkene stage is more exothermic (low energy) than the hydrogenation at the alkane stage (Pd/C is used as catalyst)

Question 81

Finely divided platinum metal, precipitated onto a calcium carbonate support.

Answer 81

Lindlar Catalyst

Question 82

Lindlar catalyst is a finely divided platinum metal, precipitated onto a calcium carbonate support and deactivated by treatment with ________ and ________.

Answer 82

lead acetate, quinoline

Question 83

There’s an alternative method used in the reduction of alkynes aside from using the reagents H2 and Lindlad Catalyst. What are those?

Answer 83

Na/Li in a liquid NH3.

Question 84

What alkenes are produced in the reduction of alkynes using Na/Li in liquid NH3? cis or trans?

Answer 84

trans alkanes

Question 85

Alkynes can be cleaved with powerful oxidizing agents such as _______ and KMnO4.

Answer 85

Ozone

Question 86

What products are formed from the cleavage of an internal alkyne? How about in a terminal alkyne?

Answer 86

Carboxylic acid, CO2 as one of products.

Question 87

Carbocations are planar. True or False?

Answer 87

True

Question 88

Terminal alkynes are relatively basic. True or False?

Answer 88

False. Acidic

Question 89

When terminal alkyne is reacted with a strong base such as _______, _______ hydrogen is removed and acetylide _______ is formed.

Answer 89

Na+NH2, terminal, anion

Question 90

Reaction is a reaction where there is a choice of pathway, but the product is formed from the more favorable reaction pathway

Answer 90

Stereoselective

Question 91

Why terminal alkynes are acidic & more stable? In other words, why are acetylide anions stable than vinylic or alkylic anions?

Answer 91

Because of the hybirdization of megatively charged carbon atom having a 50% s-character.

Question 92

What makes acetylide anions a strong nucleophile?

Answer 92

Due to its negative charge and unshared unpaired electrons.

Question 93

A process where a new alkyl group has attached to the starting alkyne.

Answer 93

Alkylation

Question 94

Is alkyne alkylation limited to acetylene?

Answer 94

No. Any terminal alkyne reacted with alkyl halide yields a internal alkyne product.

Question 95

What reagents are used in the alkylation of acetylide anions?

Answer 95

1. NaNH2, NH3 2. CH3CH2CH2CH2Br

Question 96

What the only limit to the alkylation reaction?

Answer 96

It can only use primary alkyl bromides and alkyl iodides.

Question 97

Why does alkylation reaction can only use primary alkyl bromides and alkyl iodides?

Answer 97

because acetylide ions are sufficiently strong bases to cause elimination instead of substitution.

Question 98

A reaction is __________ if it selectively produces one constitutional isomer when multiple outcomes are possible. It determines where a reaction occurs within a molecule

Answer 98

Regiospecific

Question 99

A reaction is _________ if a particular stereoisomer of the reactant leads to a specific stereoisomer of the product. It determines how the spatial arrangement of atoms changes

Answer 99

Stereospecific

Question 100

Have the same configuration in at least one center but opposite configurations at the others

Answer 100

Dienantiomers

Question 101

are diastereomers that differ in configuration at only one chirality center

Answer 101

Epimers

Question 102

___________ contain chirality centers but are achiral overall because they have a plane of symmetry.

Answer 102

Meso compound

Question 103

A ________ is one that does not contain a plane of symmetry cutting through it so that one half is a mirror image of the other half

Answer 103

Chiral molecule

Question 104

The most common cause of chirality in organic molecules is the presence of a tetrahedral, _______- hybridized carbon atom bonded to four different groups- a so-called _________.

Answer 104

sp3, chirality center

Question 105

Reactions are selective for one functional group over another – for example, a reaction that selectively reacts with alkynes in the presence of alkenes

Answer 105

chemoselective

Question 106

Reactions are selective for the formation of one constitutional isomer over another – for example, the “Markovnikov-selective” addition of strong acids to alkenes is an example of _________.

Answer 106

Regioselective

Question 107

states that when there is more than one possible beta carbon that can be deprotonated while performing an elimination reaction, the more substituted one (the one with fewer hydrogen atoms attached) is preferred.

Answer 107

Zaitzev’s Rule

Question 108

A hydrocarbon that contains a triple bond.

Answer 108

Alkyne

Question 109

Acetylene is a ______ molecule with bond angles of _______.

Answer 109

linear, 180 degrees

Question 110

Pi bonds in the triple bond are formed by the ________ -overlap of p orbitals.

Answer 110

sideways

Question 111

Polar process: adding protons Radical process: addition of single electrons True or False?

Answer 111

True

Question 112

hydrohalogenation is a polar reaction

Answer 112

True. due to the polarized halogen.