Alcohols

Question 1

Preparation of alcohols from alkanes

CnH2n + H20—->?

Answer 1

CnH2n + H20–H+–>CnH2n+2 O

Question 2

Preparation of alcohols from hydroboration oxidation

CH3-CH=CH2+ (H-BH2)2—>?

Answer 2

CH3-CH=CH2+ (H-BH2)2—>CH3-CH2-CH2-BH2

Question 3

Preparation of alcohols from carbonyl compounds 
R-CHO+H2---->?
R-COR'--NaBH4-->?
R-COOH--LiAlH4-->?
RCOOR'--H2,catalyst-->?

Answer 3

R-CHO+H2—->RCH2-OH

R-COR’–NaBH4–>R-CH(OH)-R’

R-COOH–LiAlH4–>R-CH20H

RCOOR’–H2,catalyst–>RCH2OH+R’OH

Question 4

Preparation of alcohols from Grignard’s reagent
HCHO–RMgX,H20–>?
RCHO–R’MgX,H20–>?
RCOR’–R’MgX,H20–>?

Answer 4

HCHO–RMgX,H20–>RCH2OH + Mg(OH)X

RCHO–R’MgX,H20–>R-CH(R’)-OH+ Mg(OH)X

RCOR’–R’MgX,H20–>R-C(R’)(R’’)-OH

Question 5

Preparation of alcohols by hydrolysis of alkyl halide

RX+KOH—->?

Answer 5

RX+KOH—->ROH+KX

Question 6

Preparation of alcohols by hydrolysis of ether

R-O-R+ H20–H2SO4–>?

Answer 6

R-O-R+ H20–H2SO4–>2ROH

Question 7

Preparation of alcohols from primary amines

RNH2 + HONO –NaNO2+HCl–>?

Answer 7

RNH2 + HONO –NaNO2+HCl–>ROH + N2 + H20

Question 8

Preparation of phenols from halo arenes

C6H5Cl + NaOH–623K–>?

Answer 8

C6H5Cl + NaOH–623K–>C6H5(O-)Na+ –HCl–>C6H5-OH

Question 9

Preparation of phenols from benzene Sulphonic acid

C6H5-SO3H–NaOH,H+–>?

Answer 9

C6H5-SO3H–NaOH,H+–>C6H5-OH

Question 10

Preparation of phenols from diazonium salts

C6H5-(N2+)Cl- –H20–>C6H5-OH + N2 + HCl

Answer 10

C6H5-(N2+)Cl- –H20–>C6H5-OH + N2 + HCl

Question 11

Preparation of phenols from cumene

C6H5-CH(CH3)-CH3–O2,H+–>?

Answer 11

C6H5-CH(CH3)-CH3–O2,H+–>C6H5-OH + CH3COCH3

Question 12

Reactions of alcohols:
Esterification
Ar/R-OH+R'COOH--H+-->?
Ar/R-OH+(R'CO)2O--H+-->?
Ar/R-OH+R'COCl--pyridine-->?

Answer 12

Ar/R-OH+R’COOH–H+–>Ar/R-OCOR’+ H20

Ar/R-OH+(R’CO)2O–H+–>Ar/R-OCOR’+ R’COOH

Ar/R-OH+R’COCl–pyridine–>Ar/R-OCOR’+HCl

Question 13

Reaction of alchols from halogen acids

R-OH+HX—->?

Answer 13

R-OH+ HX—>RX + H20

Question 14

Reaction of alcohols with phosphorous halides

ROH+ PCl5—->?

Answer 14

ROH+ PCl5—->RCl+POCl3+ HCl

Question 15

Reaction of alchols with thionyl chlorides

ROH+ SOCl2—->?

Answer 15

ROH+SOCl2—-> RCl + SO2 + HCl

Question 16

Reaction of alcohols:
Dehydrogenation
RCH2OH--Cu/300 C-->?
RCHOH-R--Cu/300 C-->?
(CH3)3COH--Cu/300 C-->?

Answer 16

RCH2OH–Cu/300 C–>RCHO

RCHOH-R–Cu/300 C–>RCOR

(CH3)3COH–Cu/300 C–>CH3-C(CH3)=CH2

Question 17

Reaction of phenols:
Halogenation
C6H5-OH+ Br2(Excess)—->?

Answer 17

C6H5-OH+ Br2(Excess)—->2,4,6 tribromophenol

Question 18

Reaction of phenols :
Sulphonation
C6H5-OH–conc H2SO4–> ?

Answer 18

C6H5-OH–conc H2SO4–> o-hydroxybenzene Sulphonic acid + p- hydroxybenzene Sulphonic acid

Question 19

Rection of phenols:
Nitration
C6H5-OH–conc HNO3,conc H2SO4–> ?
C6H5-OH–dil HNO3, room temp–> ?

Answer 19

C6H5-OH–conc HNO3,conc H2SO4–> 2,4,6 trinitrophenol

C6H5-OH–dil HNO3, room temp–> o-nitro phenol + p-nitro phenol