Alkenes

Question 1

Types of isomerism shown by alkenes

Answer 1

Geometric and structural isomerism

Question 2

What is cis trans isomerism called?

Answer 2

Stereoisomerism

Question 3

Does cis or trans have more BP, MP and more polar?

Answer 3

Cis from has more BP and is more polar than trans form. Trans form has higher MP.

Question 4

EZ notation full form

Answer 4

E stands for Entgegen(meaning opposite) and Z stands fro zusammen(meaning together)

Question 5

Which method produce alkenes of cis geometry ?

Answer 5

Production of alkenes from alkynes using Lindlar’s Catalyst

Question 6

What is Lyndlar’s catalyst? In which reaction is it used?

Answer 6

Partially deactivated palladised charcoal. It is used to convert alkynes to alkenes. It’s Pd

Question 7

Which recation allows production of trans alkenes? What are the conditions for such a reaction?

Answer 7

Birch reduction. Alkynes on reduction with sodium and liquid ammonia yields trans alkenes.

Question 8

For dehydrohalogenation, what catalyst is used? Order off Ease of dehydrohalogenation or order for reactivity for such reactions wrt halogens is?

Answer 8

Alcoholic KOH. Iodine> Bromine> Chlorine

Question 9

For formation of alkenes from vicinal dihalides, catalyst used?

Answer 9

Zn. Catalysts: Alcohol, heat

Question 10

(A)Order of reactivity of halogens to alkenes in halogenation reaction? Catalyst used?
(B)Which Halogen doesn’t show addition of halogens normally?
(C)Which of these halogen solutions is used as test for unsaturation?

Answer 10

(A) E>Cl>Br>I . CCl4
(B) Iodine
(C) Reddish orange colour of bromine solution in carbon tetrachloride is discharged when bromine adds up to an unsaturation site.

Question 11

Examples of Electrophilic addition reaction

Answer 11

Addition of hydrogen halides,

Question 12

Reactions that produce unsymmetrical alkenes

Answer 12

Addition of hydrogen halides

Question 13

Reactivity order of hydrogen halides? What is peculiarity of HBR?

Answer 13

HI>HBR>HCL. HBR shows Anti Markonikov wherease other’s don’t.

Question 14

HCl + CH3CH=CH2 {CATALYST: Peroxide} forms?

Answer 14

Ch3CHCLCH3, HCL and HI are not affected by peroxide effect.

Question 15

THF

Answer 15

Tetra hydro furan

Question 16

Catalyst for hydroboration oxidation?

Answer 16

(i)B2H6/THF (ii)H2O2/OH-

Question 17

RCH=CH2 Gives {CATALYST: BRH6/THF}

Answer 17

(RCH2CH2)3B

Question 18

Demercuration Catalyst?

Answer 18

NABH4[ for removing Hg(OAC)2 ]

Question 19

Baeyer’s Reagent

Answer 19

KMNO4

Question 20

Condition for Alkenes to produce vicinal diols under oxidation?

Answer 20

H2O {CATALYST:Cold dilute aqueous KMNO4, 273K}

Question 21

Tests for unsaturation?

Answer 21

(I)Decolorization of KMNO4 from oink to colorless if there is unsaturation
(II)Hbr’s reddish brown colour discharged in presence of ccl4 and unsaturated carbon.

Question 22

(I)Aqueous NaOH
Reflux
(II)Mg in dry ether
Reflex
(III)PCI5
Room temperature
(IV)HNO3 and H2SO4
55C
(V)CI3 and AICI3
Warm gently
(VI)CH3CH2CI and AICI3
Warm gently
(VII)HCI and NaNO2
Below 5C

Answer 22

(I)Nucleophilic substitution, converts haloalkanes to alcohols. Converts Choro-Benzene to Benzene with help of Ni-Al
(II)Used to make Grignard reagents with haloalkanes.
(III)Chlorinating agent, reacts with OH group in alcohols and carboxylic acids
(IV)Adds NO2 group onto benzene ring.
(V)Adds CI group onto benzene ring.
(VI)Adds CH3CH2 group onto benzene ring.
(VII)Forms diazonium salts with phenylamine/Aniline.

Question 23

Aldehydes are the first oxidation products of:

Answer 23

Primary Alcohols

Question 24

Succinate

Answer 24

C4H4O4

Question 25

Which one of the following classes of compounds is obtained by polymerization of acetylene?

(1) Poly-ene

(2) Poly-yne

(3) Poly-amide

(4) Poly-ester

Answer 25

Poly-Yne

Question 26

Reaction using Na, liquid Nh3

Answer 26

Hydrogenation of alkynes(Addition of H2) takes place in the presence of Na/liqNH3. This is known as birch reduction. In birch reduction, trans alkene is formed.

Question 27

Alkenes on reaction with KMno4 and then reacting with H2SO4 under Heat forms Di carbaldehyde

Question 28

When Benzen reacts with Clhorine in presence of sunlight, formed?

Answer 28

C6H6CL6 as all double bonds broken