Lesson 4: Alkynes

Question 1

A hydrocarbon with double bonds

Answer 1

Alkenes

Question 2

Unsaturated hydrocarbon where some hydrogen have been replaced by triple carbon-carbon bonds. (replaced by pi bonds)

Answer 2

Alkynes

Question 3

General formula of alkynes

Answer 3

CsubnHsub2n-2

Question 4

In the general formula of alkynes n represents

Answer 4

Number of carbon atoms

Question 5

Carbons in triple bond are ______________ and have linear geometry

Answer 5

sp hybridized

Question 6

1 sigma bond and 2 pi bonds=

Answer 6

3 bonds

Question 7

Carbon triple bond is _________ than carbon double bond

Answer 7

Stronger

Question 8

Unsaturated Hydrocarbons are easy to break. Opening opportunity for __________.

Answer 8

Reactions

Question 9

Open bonds from the uncoiling of triple and double bonds, the opened bonds could provide connections for carbon atoms to attach to, a process we call ______________.

Answer 9

Polymerization

Question 10

In the rules for naming alkynes, you need to find the longest carbon chain that includes both _________ of the ___________.

Answer 10

Carbons, triple bonds

Question 11

Rules for naming alkynes: Number the longest chain starting at the end _________ to the triple bond.

Answer 11

Closest

Question 12

Rules for naming an alkyne:
Label each of the ___________ at its corresponding carbon.

Answer 12

Substituents

Question 13

If there are more than one of the same substituent use the prefixes ____, ____, and ______ and so on.

Answer 13

di, tri and tetra

Question 14

Rules for naming an alkyne:
If there is an alcohol present, number the longest chain starting at the end closest to it. However, the suffix would be ________, because the alcohol takes priority over the triple bond.

Answer 14

—ynol

Question 15

Rules for naming an alkyne:
When there are two triple bonds in the molecule, find the longest carbon chain including both the __________. The suffix that would be used to name this molecule would be —diyne.

Answer 15

Triple bonds

Question 16

Rules for naming an alkyne:
Substituents containing a triple bond are called _________.

Answer 16

Alkynyl

Question 17

Rules for naming an alkyne:
A molecule that contains both double and triple bond is called an __________. The chain can be numbered starting with the end closest to the functional group that appears first.

Answer 17

Alkenyne

Question 18

Alkyne nomenclature: Common name
The basis of all common Name for alkyne is the simplest form of alkyne—__________.

Answer 18

Acetylene

Question 19

Consists of a closed ring of carbon atoms containing one or more triple bonds.

Answer 19

Cycloalkyne

Question 20

The linear nature of alkyne unit makes cycloalkyne _________. Hence, they are very occurring organic compounds.

Answer 20

Strained

Question 21

General formula of cycloalkyne

Answer 21

CsubnHsub2n-4

Question 22

Physical properties of alkyne:
Alkynes are ________, __________ with characteristics that are comparable to those of Alkanes and alkenes.

Answer 22

Unsaturated, nonpolar hydrocarbons

Question 23

Physical properties of alkynes:
Molecules with a _________ between carbon atoms.

Answer 23

Triple bond

Question 24

Physical properties of alkynes:
Two types of alkynes

Answer 24

Terminal and internal

Question 25

Physical properties of alkyne: A carbon-carbon triple bond at the end of the carbon chain.

Answer 25

Terminal alkynes

Question 26

Are those that have a carbon-carbon bond in the middle of the carbon chain.

Answer 26

Internal alkynes

Question 27

Boiling and melting point: Alkynes have a ___________ because they contain a triple bond.

Answer 27

Higher boiling point

Question 28

Boiling point and melting point: ____________ is more susceptible to distortion due to the increased number of weakly held electrons in the compound.

Answer 28

Electric field

Question 29

Boiling and melting points: Alkynes have higher boiling points because of their ______________.

Answer 29

Linear structure

Question 30

Boiling and melting points: Alkynes rise in proportion to the size of their ____________.

Answer 30

Molecular structures

Question 31

Boiling point: Alkynes, like ethyne, has linear structure because the carbon atom underwent _____________.

Answer 31

sp hybridization

Question 32

Boiling point: Boiling rises with the increase in molar mass for a group of ______________.

Answer 32

Subsequent alkynes

Question 33

Density: Alkynes are lighter and has ________ density than water

Answer 33

Lower

Question 34

Density: Alkynes become more dense as _______ increases.

Answer 34

Mass

Question 35

Physical state: Alkynes are _______ and ________.

Answer 35

Odorless and colorless

Question 36

Physical state: The first three alkynes are ______,and the next eight alkynes are _________.

Answer 36

Gases, liquids

Question 37

Physical state: All alkynes higher than 11 alkynes are ________.

Answer 37

Solids

Question 38

Physical state: The first three alkynes that are all gaseous substances.

Answer 38

Ethyne, propyne and butyne

Question 39

Solubility: Alkynes ________ in organic solvents.

Answer 39

Dissolve

Question 40

Solubility: Alkynes have slight solubility in ______________.

Answer 40

Polar solvents

Question 41

Solubility: Alkynes are ________ in water.

Answer 41

Insoluble

Question 42

Polarity: Alkynes are _________ due to slight solubility in polar solvents and insoluble in water.

Answer 42

Nonpolar

Question 43

Polarity: Alkynes are more __________ than alkenes and alkanes.

Answer 43

Electronegative

Question 44

Alkynes are more electronegative than alkenes and alkanes due to their _________ carbon atom.

Answer 44

sp hybridized

Question 45

Reaction of alkynes: The principal reaction of the alkynes is _______ across the triple bond to form alkanes.

Answer 45

Addition reaction

Question 46

Alkynes undergo catalytic hydrogenation with the same catalysts used in _____________.

Answer 46

Alkene hydrogenation

Question 47

Alkyne hydrogenation follows the same process as _______________.

Answer 47

Alkene hydrogenation

Question 48

In low temperature liquid ammonia, alkynes can also be __________ with sodium.

Answer 48

Hydrogenated

Question 49

The process for adding halogens to an alkyne is the same as for adding halogens to alkenes.

Answer 49

Halogenation

Question 50

Hydrogen halides react with alkynes in the same manner as they do with alkenes.

Answer 50

Hydrohalogenation

Question 51

The addition of the elements of water across the triple bond of an alkyne leads to the formation of Aldehydes and Ketones.

Answer 51

Hydration

Question 52

Water adds across the triple bond of an alkyne via a ______________.

Answer 52

Carbocation mechanism

Question 53

Alkynes are oxidized by the same reagents that oxidize alkenes.

Answer 53

Oxidation

Question 54

Ozonolysis of an alkyne also leads to ______________.

Answer 54

Carboxylic acid formation

Question 55

Alkynes can be polymerize by both _________ and _________ methods.

Answer 55

Cationic and free-radical

Question 56

Alkynes can be polymerized by both cationic and free-radical methods.

Answer 56

Polymerization

Question 57

Alkynes undergo many of the same reactions as alkenes, but can react twice because of the presence of the two _______ in the triple bonds.

Answer 57

Pi bonds

Question 58

Three isomers of pentyne:

Answer 58

Pent-1-yne, pent-2-yne and 3-methylbut-1-yne

Question 59

Triple-bonded carbons are sp-hybridized, and have linear shapes, with the bonded atoms at angles of ______ to each other. Because of this linear shape, geometric isomerism does not occur in alkynes.

Answer 59

180°

Question 60

The simplest of the alkynes, consisting of two carbon atoms connected by a triple bond, leaving each carbon able to bond to one hydrogen atom.

Answer 60

Ethyne (acetylene)

Question 61

It is due to the different arrangement of carbon atoms in the chain that is straight-chain or branched.

Answer 61

Chain isomerism

Question 62

It is due to the difference in the location of the triple bond.

Answer 62

Position isomerism

Question 63

Alkynes are isometric with alkadienes both being represented by the general formula CsubnHsub2n-2.

Answer 63

Functional isomerism