Factual Learning

Question 1

Is Na2Cr2O7 hygroscopic?

Answer 1

Yes

Question 2

BDC+ hypophosphorus acid

Answer 2

Benzene + nitrogen gas+ phosphorous acid+ HCl

Question 3

Heating of benzene sulphonic acid in acidic medium gives at 100°C

Answer 3

Benzene+ sulphuric acid

Question 4

Heating of benzene sulphonic acid in acidic medium gives at 100°C

Answer 4

Benzene+ sulphuric acid

Question 5

Phenyl magnesium bromide with 1) dil . Acid
2) alkali

Answer 5

1) benzene 2) phenol

Question 6

Benzene with Fenton’s reagent

Answer 6

Fenton’s reagent is FeSO4 + H2O
F.R + benzene —> phenol

Question 7

Phenol + Zn dust —>

Answer 7

Benzene + zinc oxide

Question 8

N-hexane +Cr2O3 (or) Mo2O3 —>

Answer 8

Benzene +4 H2

Question 9

Intermediate in eas reactions of benzene or aromatic compounds is

Answer 9

Whelan intermediate (arenium complex )

Question 10

What is added in the iodination of benzene to increase forward product?

Answer 10

Oxidising agents like HNO3, HIO3,HgO etc converts HI to I2

Question 11

Is there isotopic effect in nitration of benzene?

Answer 11

No , removal of hydrogen is fast step in nitration of benzene, hence no isotopic effect.

Question 12

Nitrating agents

Answer 12

N2O5 in CCl4, NO2+BF4- , NO2+PF6-, also HNO3 , CONC. HNO3 + OLEUM

Question 13

Is isotopic effect present in sulphonation of benzene?

Answer 13

Yes, sulphonation is a reversible process . Removal of hydrogen is also a slow step.

Question 14

Sulphonating Agents

Answer 14

Oleum, pyrosulphuric acid

Question 15

What type of carbonation is formed in Friedel crafts alkylation with 1 ) anhy. AlCl3 2) anhydrous FeCl3

Answer 15

1) free carbonation ( rearrangement possible)
2)no free c+ (no rearrangement )

Question 16

Name products when benzene reacts with
1. Vinyl halide
2. Aryl halide
3. Dichloromethane
4. Chloroform
5. Carbon tetrachloride in presence of AlCl3 anhydrous

Answer 16

1. No reaction
2. No reaction
3. Diphenyl methane
4. Triphenyl methane
5. Triphenyl chloro methane, tetraphenyl methane is not formed due to steric hindrance.

Question 17

Benzene + COCl2

Answer 17

Benzophenone

Question 18

Nitrobenzene / benzaldehyde + methyl chloride (AlCl3)

Answer 18

No reaction
Friedel crafts acylation or alkylation doesn’t occur in presence of electron withdrawing group . Aniline also cannot undergo Friedel crafts reactions as it forms complex with AlCl3.

Question 19

About reagent BF3?

Answer 19

BF3 acts as Lewis acid and free carbonation is formed.

Question 20

Can benzene undergo afdition reaction in drastic conditions

Answer 20

Yes. Benzene reacts with chloride gas in presence of heat , sunlight/ high pressure and sunlight to give benzene hexachloride or Gammaxane.(called as 666 or Lindane or BHC, used as insecticide).

Question 21

Benzene + chlorine gas in cold dark conditions

Answer 21

Hexachloro benzene

Question 22

1. Benzene+ oxygen in vanadium pentoxide(300°C)
2. Benzene+ excess oxygen in V2O5 500°C

Answer 22

1.Phenol.
2. Maleic anhydride.

Question 23

Reagents to convert alkyl benzene with alpha hydrogen attached to sp3 carbon into benzoic acid is

Answer 23

Alkaline hot KMnO4; acidic hot KMnO4; acidic K2Cr2O7

Question 24

Products of nitration of benzene at
1. Less than 60°
2. =90°
3. Greater than 90°

Answer 24

1. Nitrobenzene
2. 1,3-dinitrobenzene
3. 1,3,5- trinitobenzene(less yield)

Question 25

Free radical mechanism reagents

Answer 25

SO2Cl2 in sun light(sl) , peroxide, cl2 sl, br2 sl NBS, NCS( allylic , benzylic free radical substitution)

Question 26

When is the prefix benzyl, benzal , benzoic, used?

Answer 26

Benzyl is used when. -CH2-C6H5 Benzal is used when. -CH-C6H5 Benzo is used when. -C-C6H5

Question 27

What is chloral and what if formed when chloral reacts with chlorobenzene?

Answer 27

Chloral- trichloroacetaldehyde Product formed is DDT (dichloro diethyl trichloroethane) which is an insecticide

Question 28

Hyper conjugation order for -CH3, -CD3, -CT3

Answer 28

-CH3> -CD3> -CT3

Question 29

Propyne reacts with red hot Cu or Fe tube to give

Answer 29

Mesitylene ( 1,3,5-trimethyl benzene)

Question 30

Sabatier Sender's reaction

Answer 30

Alkene + H2 in Ni(200°C) or Pd/Pt/Ru/Rh at room temp. Syn addition Methane cannot be prepared.