Alkynes and cycloalkynes

Question 1

unsaturated hydrocarbons where some hydrogens have been replaced by triple carbon-carbon bonds

Answer 1

alkynes

Question 2

General Formula of alkynes

Answer 2

CnH2n-2

Question 3

Carbons in triple bond are __ __ and have __ geometry

Answer 3

• sp hybridized
• linear

Question 4

sp hybridized angle

Answer 4

180

Question 5

sp2 hybridized angle

Answer 5

120

Question 6

sp3 hybridized angle

Answer 6

109.5

Question 7

3 bonds of alkynes

Answer 7

• 1 sigma bond
• 2 pi bonds

Question 8

carbon triple bond is __ than carbon double bond

Answer 8

stronger

Question 9

bond length of triple bonds compared to double bonds

Answer 9

shorter

Question 10

__ __ are easy to break. Opening opportunity for reactions

Answer 10

unsaturated hydrocarbons

Question 11

open bonds from the uncoiling of triple and double bonds, the opened bonds could provide connections for carbon atoms to attach to

Answer 11

polymerization

Question 12

How to name alkynes

Answer 12

1. find longest chain with triple bond
2. start counting closest to triple bond
3. in presence of alcohol, number starting to closest alcohol

Question 13

suffix of alkynes with alcohol

Answer 13

-ynol

Question 14

name of alkyne that is a substituent

Answer 14

alkynyl (ex. ethynyl)

Question 15

molecule that contains both double and triple bonds

Answer 15

alkenyne

Question 16

how to number alkenyne

Answer 16

starting end closest to the functional group that appears first

Question 17

simplest form of alkyne

Answer 17

acetylene (ethyne)

Question 18

consist of closed ring of carbon atoms containing one or more triple bonds

Answer 18

cycloalkyne

Question 19

the linear nature of alkyne unit makes cycloalkynes __

Answer 19

strained

Question 20

because of linear nature of alkynes, cycloalkynes are __ __ occuring organic compounds

Answer 20

very rare

Question 21

General Formula of cycloalkynes

Answer 21

CnH2n-4

Question 22

Two types of alkynes

Answer 22

1. terminal
2. internal

Question 23

a carbon-carbon triple bond at the end of the carbon chain

Answer 23

terminal alkynes

Question 24

carbon-carbon triple bond in the middle of the carbon chain

Answer 24

internal alkynes

Question 25

boiling point of alkynes compared to other hydrocarbons

Answer 25

higher boiling point

Question 26

electric field of alkynes

Answer 26

more susceptible to distortion

Question 27

why is the electric field of alkynes more susceptible to distorition

Answer 27

due to increased number of weakly held electrons

Question 28

boiling points of alkynes rise in proportion to the

Answer 28

size of molecular structres

Question 29

boiling points of alkynes rise with the increase of

Answer 29

molar mass

Question 30

density of alkynes

Answer 30

- lighter, lower density than water - become more dense as mass increases

Question 31

physical state of alkynes

Answer 31

- odorless, colorless - first three alkynes are gases - next eight alkynes are liquid - all alkynes higher than there are solids

Question 32

physical state: 2-4 carbon alkynes

Answer 32

gases

Question 33

physical state: 5-12 carbon alkynes

Answer 33

liquid

Question 34

physical state: 13 and above carbon alkynes

Answer 34

solid

Question 35

solubility of alkynes

Answer 35

- dissolve in organic solvents - slight solubility in polar solvents - insoluble in water

Question 36

example of non polar organic solvents

Answer 36

- benzene - ether

Question 37

polarity of alkynes

Answer 37

- nonpolar - more electronegative than alkenes and alkanes

Question 38

why are alkynes more electronegative than alkanes and alkenes

Answer 38

due to sp hybridized carbon atom

Question 39

Alkynes: addition reactions

Answer 39

addition across triple bond to form alkanes

Question 40

Different addition reactions of alkynes

Answer 40

1. hydrogenation 2. halogenation 3. hydrohalogenation 4. hydration 5. oxidation 6. polymerization

Question 41

- an addition reaction where hydrogen molecules are used to saturate organic compounds - process is effective under certain catalytic conditions and controlled temperatures depending on the type of hydrocarbon - undergo the same with the same catalysts used in alkene

Answer 41

hydrogenation

Question 42

- involves the reaction of a compound with a halogen and results in the halogen being added to the compound - possible to stop this reaction at alkene stage by runnint it at temperature slightly below 0C

Answer 42

halogenation

Question 43

- When hydrogen halide is treated with alkynes (triple bond compounds) it results in the formation of gem halides. - Gem halides are the compounds in which two halogens are attached to the same carbon atoms in a molecule.

Answer 43

hydrohalogenation

Question 44

compounds in which two halogens are attached to the same carbon atoms in a molecule

Answer 44

Gem halides

Question 45

- addition of water to alkynes - formes aldehydes and ketones

Answer 45

hydration

Question 46

what is formed after hydration of alkynes

Answer 46

- aldehydes - ketones

Question 47

hydration in alkynes

Answer 47

water across triple bond via carbocation mechanism

Question 48

loss of electrons during a reaction by a molecule, atom or ion

Answer 48

Oxidation

Question 49

Alkynes undergo ozonolysis to give

Answer 49

- acid anhydrides or diketonesion - carboxylic acid

Question 50

alkynes can be polymerized by both

Answer 50

- cationic methods - free-radical methods

Question 51

because of the linear shape of alkynes, __ __ does not occur

Answer 51

geometric isomerism

Question 52

- due to the different arrangment of carbon atoms in the chain that is straight-chain or branched

Answer 52

chain isomerism

Question 53

- due to the difference in the location of triple bond

Answer 53

position isomerism

Question 54

- alkynes are isomeric with alkadienes both being represneted by the general formula CnH2n-2

Answer 54

functional isomerism