Hydrocarbons

aliphatic hydrocarbons

the carbon atoms are attached to another carbon to form chains

saturated hydrocarbons

compounds in which all the valencies of carbon atoms are fully satisfied by single bonds

alkanes

examples of saturated hydrocarbons

unsaturated hydrocarbons

compounds in which all the valencies of carbon atoms are not fully utilised

alkenes and alkynes

examples of unsaturated open chain hydrocarbons

cyclic hydrocarbons

hydrocarbons which contain closed chain of carbon atoms

cyclo alkanes and cyclo alkenes

cyclic hydrocarbons

CnH2n

general formula for cycloalkanes

aromatic hydrocarbons

special class of cyclic compounds containing benzene ring

benzene

other aromatic compounds are the derivatives of ...

Methane

major constituent of natural gas , 94%

anhydrous sodium acetate, soda lime

when ...is heated with...it forms methane

methane

when anhydrous sodium acetate is heated with soda lime it forms...

anhydrou sodium acetate

most convenient method for the preparation of methane

methane

reduction of methyl iodide with nascent hydrogen gives us

palladium

catalyst in catalytic reduction of methyl iodide

hydrolysis

methyl magnesium iodide on ...gives methane

substitution reaction

halogenation is a ...

Chlorination

example of free radical chain reaction

chlorination of methane

photochemical dissociation of chlorine, chlorine free radical attacks methane and forms methyl free radical, then this free radical removes chlorine atom from another chlorine molecule and form chloro methane and chlorine free radical

ethane

reduction of ethyl iodide with nascent hydrogen gives...

zinc copper couple and ethanol

in the reduction of ethyl iodide nascent hydrogen is obtained from ...

wurtz reaction

2Ar / R Halides react with sodium in dry ether to give hydrocarbons containing double the number of carbon atoms present in the halide.

ethane

methyl iodide with sodium metal in ether solvent gives...

nickel

catalytic hydrogenation of ethene , the catalyst is ...

300°

catalytic hydrogenation of ethene temperature

ethane

catalytic hydrogenation of ethene gives ...

ethene

when ethanol is heated with concentrated sulphuric acid at 170°C it gives ...

Al2O3, H3PO4/Al2O3

ethanol can be converted to ethene by passing the vapors of ethanol over catalyst

free radical initiation

More radicals in products than reactants

ethene

dehydrohalogenation of Ethyl chloride gives ...

alcoholic potassium hydroxide

when ethyl chloride is treated with .... it gives ethene

vicinal dichloride

1,2 dichloroethane

ethene

dehalogenation of vicinal dichloride with zinc metal powder gives...

ethene

ethyne on hydrogenation with Nickel as catalyst at 200°C gives....

electrophilic reagents

pi bond provides electron to the reagent that is seeking electrons

ethane

hydrogenation of ethene in the presence of nickel at 300°C gives ...

cl2>br2>I2

reactivity of halogens in addition of halogens

1,2 dihalo ethane

halogenation of ethene gives

halo ethane

hydrohalogenation of ethene gives ....

HI>HBr> HCl

reactivity in hydrohalogenation of ethene

chloroethanol and chloroethane

halohydration of ethene gives

polyethene

ethene polymerizes at 200°C and under 100atm in the presence of oxygen to form ...

sp2

each carbon of ethene is ...hybridized

2 sigma bonds with 2 hydrogen atoms

out of 3 sp2 hybrid orbitals, two orbitals of each carbon atom are utilised in the formation of ...

sigma bond between 2 carbon atoms

third sp2 hybridised orbital of one carbon overlaps with sp2 hybridised or orbital of second carbon and forms...

pi bond

the remaining Pz orbital of each carbon atom undergoes parallel overlapping with one another and form second bond between two carbon atoms ....

sp3 hybridised, 4

each C atom of ethane is ....containing ...sp3 hybrid orbitals

sigma bonds with 3 hydrogen

out of four sp3 hybrid orbitals of each C atom , 3 hybrid orbitals are utilised in the formation of ....

overlaps with sp3 hybrid orbitals of other carbon atom to form a sigma orbital

the remaining sp3 hybrid orbitals of one C atom ...

Ethyne

present in oil gas and coal gas upto 10%

action of cold water on calcium carbide

ethyne

acetylene

dibromoethane on boiling with alcoholic KOH produces ...

ethene then ethane

hydrogenation of ethyne at 200°C in the presence of Nickel

chloro and bromo derivatives

ethyne reacts with cl2 and Brian in the presence of catalyst and forms ....

1,1-dibromoethane

hydrohalogenation of vinyl bromide gives ...

hydration of ethyne

ethyne reacts with water in the presence of HgSO4 and H2SO4 at 75°C to produce intermediate vinyl alcohol which then forma ethanal

substitution by Na

when acetylene is passed over heated sodium both the monosubstituted and disubstituted acetylides are formed

ammonia cuprous acetylide

when acetylene is heated with AgNO3 ....is produced

silver acetylide

when acetylene is heated with AgNO3 ....is formed

acidic properties

in the substitution of heavy metals in alkyne the reactions show ....

Faraday 1825

benzene was first isolated by ....

hofmann 1845

benzene was found to be one of the constituents of coal tar by...

12 sigma bonds

how many sigma bond is benzene

Benzene shape

a regular hexagonal with an inscribed circle or a hexagonal with alternate single and double bonds

pi electrons

what is responsible for the electrophilic substitution reactions of benzene

pi system of benzene to yield a delocalized carbocation known as arenium ion

in electrophilic substitution an electrophile attacks the...

attack by electrophile, formation of sigma complex, loss of proton , formation of substitution product

electrophilic substitution reaction

halogenation, nitration,sulphonation, alkylation and acylation

substitution reactions of benzene

halogenation of benzene

benzene reacts with bromine and chlorine in thr presence of Lewis acid catalyst at 25°C to yield bromo benzene and chloro benzene

90%

chlorobenzene formed in halogenation of benzene

75%

bromobenzene formed in halogenation of benzene

Electrophile

the function of the Lewis acids catalyst is to provide an ,,, a positive halogen ion for transfer to the benzene ring

Nitration of benzene

mixture of conc HNO3 and conc H2SO4 in the ratio of 1:1

electrophile the nitronium ion

the function of the conc H2SO4 is to increase the rate of reaction by increasing the concentration of the....

sulphonation of benzene

fuming sulphuric acid at room temp reacts with benzene to produce benzene sulphonic acid

sulphur trioxide

sulphonating reagent

Friedel-Crafts Acylation

introduction of a suitable acyl halide in presence of Lewis acid catalyst AlCl3

Friedel-Crafts reaction

the introduction of alkyl or acyl group to the benzene ring

R- and R-C=O

alkyl group and acyl group

hydrogenation of benzene

at high temo 150°C and 10 atm in the presence of Ni catalyst benzene yields cyclo hexane

halogenation of benzene

benzene will react with chlorine to give hexa chloro cyclohexane

activating and deactivating

substituent group can be classified into 2 main groups...and ...

activating group

group that cause the ring to be more reactive than benzene

deactivating group

groups that make the ring less reactive is ...

2,6

ortho position

4

para positions

3,5

meta position

alkyl, NH2, NR2 and NHCOR , OH,OR

Ortho,para- directing and activating groups

amino, alkylamino, amide,alkyl,hydroxy,alkoxy

ortho-para directing and activating groups

halogens

ortho,para directing and deactivating groups

NO2, SO3H ,COOH, COOR, CHO ,COR

Meta directing and deactivating groups

nitro,sulphonic acid, carbonyl groups like carboxylic acids,esters, aldehydes and ketones

meta directing and deactivating groups

benzoic acid

oxidation of toluene gives ...

Resonance

the process in which 2 or more structures are written for a compound which differ only in the arrangement of electrons is called...

resonance energy

difference between the energy of actual molecule and the most stable resonance structure is called...

152kj/mole

stability of benzene

delocalized

the pi electrons in benzene are ...hence they don't readily undergo a addition reaction

less reactive

benzene is...than alkenes and alkynes

initiation

net increase in number of free radical