Find the 12th Class Fsc Chemistry Online Preparation chapter 9 ( Aromatic Hydrocarbons)

Question # 1

Define two reaction which confirm presence of three double bonds in benzene ring.

Ans 1: 1.Benzene is reduced to cyclohexane on heating at high temperature which hydrogen in the presence of Pt in an acidic solvent or Ni at 200 degree as a catalyst.
2.Benzene reacts with chlorine and bromine in the presence of sunlight to give addition products ,hexachlorobenzene or hexabromobenzene.

Question # 2

What is meant by directive influence of substituent?

Ans 1: When an electrophile substitution reaction take place on the benzene ring,we get only one monosubstituted benzene all the six position in the ring are equivalent .However introduction of second group into the ring may give three isomeric distributed products ,ortho,meta and para.

Question # 3

What is meant by the terms:i) Aromatic ii) Oxidation

Ans 1: Aromatic:The term aromatic was derived from the Greek word aroma meaning fragrant and was used in organic chemistry for s special class of compounds.These compounds have low hydrogen to carbon ratio in their molecular formula and have a characteristic odour. These often produced by benzene or derivatives of benzene.
Ans 2: Oxidation:The addition of oxygen,removal of hydrogen or electrons is called oxidation.Oxidation process is carried out by some oxidizing agent like KMnO₄,K₂Cr₂O₇or V₂O₅etc.which can provide oxygen to a compound.

Question # 4

How benzene is converted into malic acid by catalytic oxidation?

Ans 1: Benzene ring is determine when it is strongly heated with air in the presence of V₂O₅as a catalyst and maleic acid is obtained.

Question # 5

What are monocyclic and polycyclic aromatic Hydrocarbons?

Ans 1: Monocyclic: Aromatic hydrocarbons containing one benzene ring in their molecules are called monocyclic aromatic hydrocarbons e.g benzene,toluene phenol,aniline benzoic acid,benzaldehyde and benzene sulphonic acid.
Ans 2: Polycyclic:Aromatic hydrocarbons containing two or more benzene rings in their molecules are called monocyclic aromatic hydrocarbons.

Question # 6

Why hydroxyl group in ortho and para directing?

Ans 1: Hydroxyl group release electron to the benzene ring .there by facilities the availability of electron to the electrophiles at ortho and para position.This result in the increase chemical reactivity of benzene ring towards electrophiles,The benzene ring can offer more than one position the new incoming group.

Question # 7

What are the major product when chlorine reacts with Toluene in the presence of sunlight?

Ans 1: When alkyl benzene are treated with chlorine or bromine in the presence of sunlight ,only the alkyl groups are submitted.

Question # 8

What is Wurtz -Fritting reaction?

Ans 1: The Wurtz reaction for the synthesis of alkanes was extended by Fitting in 1864 to the synthesis of alyl aromatic hydrocarbons.

Question # 9

What happens when Acidified KMnO₄is added to Methyl Benzene and Ethylbenzene?

Ans 1: Alkyl benzenes re readily oxidized by acidified KMnO_{4.In these reaction alkyl groups are oxidizedkeeping the benzenering intact.}

Question # 10

Define resonance energy?What is the resonance energy of benzene?

Ans 1: Benzene is more stable than the hypothetical 1,3,5-cyclohexatriene by 150.5 kj/mole.This difference between amount of heat is actually released and that calculated on the basis of the Kekule structure is called Resonance Energy Benzene shows the phenomenon of resonance which makes it more stable than others.In benzene electrons are delocalized making it a very stable molecule.The resonance energy of benzene is 150.5 kj/mole

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12th Class Fsc Chemistry Online Preparation chapter 9 ( Aromatic Hydrocarbons)

Online Short Questions For Chapter 9 "12th Class Chemistry Chapter 9 Short Questions Preparation "

Chemistry - 12th Class Chemistry Chapter 9 Short Questions Preparation

Define two reaction which confirm presence of three double bonds in benzene ring.

What is meant by directive influence of substituent?

What is meant by the terms:i) Aromatic ii) Oxidation

How benzene is converted into malic acid by catalytic oxidation?

What are monocyclic and polycyclic aromatic Hydrocarbons?

Why hydroxyl group in ortho and para directing?

What are the major product when chlorine reacts with Toluene in the presence of sunlight?

What is Wurtz -Fritting reaction?

What happens when Acidified KMnO4is added to Methyl Benzene and Ethylbenzene?

Define resonance energy?What is the resonance energy of benzene?

Prepare Complete Set Wise Questions For Chapter 9 "12th Class Chemistry Chapter 9 Short Questions Preparation "

Set 1

Set 2

12th Class Chemistry Chapter 9 Short Questions Preparation - Set 1

Define two reaction which confirm presence of three double bonds in benzene ring.

What is meant by directive influence of substituent?

What is meant by the terms:i) Aromatic ii) Oxidation

How benzene is converted into malic acid by catalytic oxidation?

What are monocyclic and polycyclic aromatic Hydrocarbons?

Why hydroxyl group in ortho and para directing?

What are the major product when chlorine reacts with Toluene in the presence of sunlight?

What is Wurtz -Fritting reaction?

What happens when Acidified KMnO4is added to Methyl Benzene and Ethylbenzene?

Define resonance energy?What is the resonance energy of benzene?

12th Class Chemistry Chapter 9 Short Questions Preparation - Set 2

Define two reaction which confirm presence of three double bonds in benzene ring.

What is the general pattern of reactivity of benzene towards electrophone?

What is meant by directive influence of substituent?

Predict major product of bromination of nitrobenzene.

What are monocyclic and polycyclic aromatic Hydrocarbons?

What objective were raised on Kekule formula of Benzene?

What is resonance?

What are aromatic hydrocarbons?Give two example.

Justify that Ethene is more reactive than C6H6.

What is meant by the terms:i) Aromatic ii) Oxidation

12th Class Chemistry Chapter 9 Preparation

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What happens when Acidified KMnO₄is added to Methyl Benzene and Ethylbenzene?

What happens when Acidified KMnO₄is added to Methyl Benzene and Ethylbenzene?

Justify that Ethene is more reactive than C₆H_6.