#4: Alkynes

Question 1

this aliphatic hydrocarbon contains a triple bond.

Answer 1

alkynes

Question 2

The general formula of alkynes

Answer 2

CnH2n-2

Question 3

• observed when one s and one p orbital in the same main shell of an atom mix to form two new equivalent orbitals.
• It forms linear molecules with an angle of 180°.

Answer 3

sp hybridization

Question 4

an orbital that is spherical with the nucleus at its centre

Answer 4

s-orbital

Question 5

an orbital that dumbbell-shaped

Answer 5

p-orbital

Question 6

A triple bond in an alkyne consists of ____ and _____

Answer 6

one sigma bond; two pi bonds

Question 7

overlap of the two p orbitals

Answer 7

pi bond

Question 8

overlapping sp orbitals, one from each atom, form a ___

Answer 8

sigma bond

Question 9

The carbon-carbon triple bond forms from two sets of overlapping ____

Answer 9

p orbitals

Question 10

Alkynes have linear geometry, and the bond angle is ____

Answer 10

180 degrees

Question 11

In alkynes of four or more carbon atoms, the triple bond can be located in different positions along the chain, leading to the formation of
_____.

Answer 11

structural isomers

Question 12

Although alkynes possess restricted rotation due to the triple bond, they do not have _______ like the alkenes because the bonding in a carbon‐carbon triple bond is sp hybridized.

Answer 12

stereoisomers

Question 13

In sp hybridization, the maximum separation between the hybridized orbitals is 180°, so the molecule is ___

Answer 13

linear

Question 14

alkynes use the suffix

Answer 14

-yne

Question 15

first rule in naming alkynes

Answer 15

Find the longest carbon chain that includes both carbons of the triple bond.

Question 16

second rule in naming alkynes

Answer 16

Number the longest chain starting at the end
closest to the triple bond.

Question 17

If there is an alcohol present in the molecule, number the longest chain starting at the end ____ to it

Answer 17

closest

Question 18

If there are two triple bonds, the suffix that would be used to name this molecule would be ____.

Answer 18

–diyne

Question 19

Substituents containing a triple bond are called

Answer 19

alkynyl

Question 19

A molecule that contains both double and
triple bonds are called an

Answer 19

alkenyne

Question 20

The chain can be numbered starting with the end _____ to the functional group that appears first.

Answer 20

closest

Question 21

what kinds of isomerism do alkynes exhibit?

Answer 21

skeletal, positional, and functional isomerism

Question 22

what kind of isomerism do alkynes not exhibit?

Answer 22

geometric isomerism

Question 23

internal alkynes are _____ than terminal alkynes.

Answer 23

more stable

Question 24

The ozonolysis of internal alkynes produces ____

Answer 24

two carboxylic acids

Question 25

the triple bond is between two carbons

Answer 25

internal alkyne

Question 26

the triple bond is flanked by hydrogen and a carbon

Answer 26

terminal alkyne

Question 27

For external alkynes, the ozonolysis results in a

Answer 27

carboxylic acid and carbon dioxide

Question 28

general formula of cycloalkynes

Answer 28

CnH2n-4

Question 29

alkynes arranged in a cyclic structure

Answer 29

cycloalkynes

Question 30

The boiling point and melting point of alkynes increase as their ____ grows bigger

Answer 30

molecular structure

Question 31

The loss of a hydrogen atom and a halogen atom from adjacent alkane carbon atoms leads to the______. The loss of additional hydrogen and halogen atoms from the double‐bonded carbon atoms leads to ______.

Answer 31

formation of alkene; alkyne formation (Dehydrohalogenation)

Question 32

In dehydrohalogenation, halogen atoms located on the same carbon are called

Answer 32

geminal dihalide

Question 33

In dehydrohalogenation, halogen atoms located adjacent carbons are called

Answer 33

vicinal dihalide

Question 34

Larger alkynes can be generated by reacting an _____, which is generated from a shorter alkyne.

Answer 34

alkyl halide with an acetylide ion (substitution)

Question 35

Ethyne is commonly called ___ is the simplest alkyne

Answer 35

acetylene

Question 36

Today, ethyne is normally prepared by the ____.

Answer 36

pyrolysis of methane

Question 37

The addition of hydrogen to alkynes may lead to the production of alkanes this is _____.

Answer 37

hydrogenation reaction

Question 38

Addition of hydrogen halides to alkenes become well known and this is formulated by ___ a Russian Chemist in 1869, better known as ____.

Answer 38

Vladimir Marconikov; Markovnicov’s rule

Question 39

Alkyne addition of water results in the formation of

Answer 39

enol and later converted to carbonyl compound