Alkenes

Question 1

Alkene

Answer 1

Hydrocarbon containing al lease one double bond (C=C)
Aliphatic unsaturated compounds
sp2 hybridization(Trigonal planar shaped,120)

Question 2

Alkene are ______ compound.

Answer 2

Aliphatic unsaturated compounds

Question 3

Hybridization of alkenes & its structure and bond angle

Answer 3

sp2 hybridization
Trigonal planar shaped,120

Question 4

General formula of alkene

Answer 4

CnH2n

Question 5

Alkenes are _______molecules.

Answer 5

electron-rich (Nucleophile)

Question 6

Bonds in alkene

Answer 6

sp2 & double bond
(one sigma bond & one pi bond)

Double bond is electron rich bcus of the movement of electrons in pi bond

Question 7

Alkene can bind with

Answer 7

Electrophile molecule (electron-deficient)

Question 8

Melting point & boiling point of alkene

Answer 8

Increase with increased no of C & H

Physical properties are increase with increased C & H

Question 9

Structural isomer of Butene

Answer 9

But-1-ene
But-2-ene

Question 10

Structural isomer of Propene

Answer 10

Pent-2-ene
Pent-1-ene

Question 11

Isomers of alkenes

Answer 11

1)Structural isomer
a.Chain isomers
b.Position isomers
2)Stereoisomerism
a.Cis-Trans isomers
b.E/Z isomers

Question 12

Stereoisomerism is

Answer 12

isomer due to restricted rotation around double bond

Question 13

Chain isomers of alkenes

Answer 13

Carbon skeleton is arranged differently
eg.But-1-ene & 2-methylprop-1-ene

Question 14

Position isomer of alkenes

Answer 14

Position of double bond in alkenes
eg.But-1-ene & But-2-ene

Question 15

Cis-trans isomers of alkenes

Answer 15

Cis isomer-2 similar gp on same side of double bond
Tran isomer-2 similar gp on opposite side with double bond

Question 16

E/Z isomers of alkenes

Answer 16

E isomer-high priority gp are on opposite sides
Z isomer-high priority gp are on the same side

Question 17

Priority rule

Answer 17

1)Atom with higher atomic number
2)Atom with longer carbon chain

Question 18

Cycloalkenes

Answer 18

Unsaturated hydrocarbon containing one or more double bond within the righ structure

Question 19

General formula for cycloalkene

Answer 19

CnH2n-2 (For monocyclic cycloalkenes with only one double bond)

Question 20

Chemical properties of alkenes

Answer 20

Addition reactions
-Addition of hydrogen (hydrogenation)
-Addition of halogen (halogenation)
-Addition of hydrogen halides (Hydrohaligenation)
-Addition of water (Hydration)
-Polymerization of alkenes

Question 21

Addition reaction of alkenes

Answer 21

-Addition of hydrogen (hydrogenation)
-Addition of halogen (halogenation)
-Addition of hydrogen halides (Hydrohaligenation)
-Addition of water (Hydration)
-Polymerization of alkenes

Question 22

Addtion of hydrogen to alkene and cycloalkenes result in

Answer 22

Alkene+H2——>alkane
Cyclealkene+H2——>Cycloalkane

Question 23

Hydrogenation of alkene

Answer 23

Addition of hydrogen
Catalyst-Nickel in 150 degree

Alkene+H2——>alkane
Cyclealkene+H2——>Cycloalkane

Question 24

Halogenation of alkene

Answer 24

Reaction takes place at room temperature

(alkane-require UV light for halogenation)

Question 25

Hydrohalogenation of symmetrical alkene

Question 26

Hydrohalogenation of asymmetrical alkene

Answer 26

*produce 2 products(One with more stable structure will be major product)

Question 27

Hydration reaction of alkene

Answer 27

2 steps 1)Addition of H2SO4 (H & HSO4) 2)Addition of water (H & OH)

Question 28

Hydration of alkene will produce

Answer 28

alcohol

Question 29

Polymerization of ethene and propene

Answer 29

Ethene-polyethene or polythene Propene-polypropene

Question 30

Classification of alkenes

Answer 30

1)Primary alkenes 2)Secondary alkenes 3)Tertiary alkenes 4)Quaternary alkenes

Question 31

Primary alkenes

Answer 31

One gp is attached to double bonded carbon

Question 32

Secondary alkenes

Answer 32

2 gp attached to double bonded carbon

Question 33

Tertiary alkenes

Answer 33

3 gp attached to double bonded carbon

Question 34

Quaternary alkenes

Answer 34

4 gps attached to double bonded carbon

Question 35

Physical properties of alkene

Answer 35

1)Nonpolar 2)Insoluble in water 3)Low bp (London dispersion force) 4)Low density than water

Question 36

State of alkene

Answer 36

2-5>gas 5-15>liquid above 16>solid