1. ORGANICCHEMISTRY
Daily Practice Problems
Q.1 Inthegivenreaction:
C6H5– CH = C + HBr 

 

Peroxide [X]
[X] willbe
(A) CH
CH
H
C
|
Br
5
6 
 (B)
Br
|
C
CH
H
C
|
Br
5
6 

(C)
Br
|
C
CH
H
C 2
5
6 
 (D) C6H5– CH = C
Q.2 Arrange the followingcarbocations inthe increasing orderoftheir stability.
(I) (II) (III)
(A*) I > II > III (B) I > II = III (C) I > III > II (D) III > I > II
[Sol. (I) Two benzenoid RS &Two H(II) Two benzenoid RS & but zero H
(III) Onlyone benzenoid RS zero H ]
Q.3 Whichstatementabout the following equilibriumis/are true?
Ph3C–H +


K
O
Me 

K
C
Ph3 + MeOH
(I) The reactionfavours the product formation.
(II) Ph3CK is the dominant anionic species in this reaction.
(III) Methanolis the weaker acidinthis reaction.
(IV) The reactionfavours the reactant formation.
(A) I & II (B) I, II & III (C*) IV only (D) III & IV
[Sol. Reaction moves towards weaker acid & base ]
Q.4 Which one of following carbonyl compound when treated with dilute acid forms the more stable
carbocation?
(A) 3
3 CH
C
CH
||
O

 (B) (C*) (D) 5
6
5
6 H
C
C
H
C
||
O


[Sol. C willformaromatic cation byattack ofHoncarbonyloxygen.]
Q.5 Correct order ofheat ofcombustionis:
(p) 1,3-Pentadiene (q) 1,3-Butadiene
(r) 2,3-Dimethyl-1, 3-butadiene (s) Propadiene
(A) s > q > p > r (B) s > r > q > p (C*) r > p > q > s (D) s > r > p > q
[Sol. More the no. ofC &H in the compound more willbe heat ofcombustion]
CLASS : XII (ALL) DPP. NO.- 22

2. Q.6 The most stable resonating structure offollowing compound is
(A) (B)
(C) (D*)
[Sol. D is octet complete R.S. with–ve on more electronegative atom"O". ]
Q.7 It required 0.7 g ofa hydrocarbon (A) to react completelywith Br2 (2.0 g). On treatment of(A) with
HBr it yielded monobromo alkane (B). The same compound (B) was obtained when (A) was treated
with HBr in presence of peroxide. Write down the structure formulae of(A) and (B) and explain the
reactionsinvolved.
Q.8 Completethe following:
CH3 – CH = CH2 + CHCl3 

 

Peroxide (A) 

 


/
Ag (B)
(E)






 


H
)
ii
(
)
excess
(
Li
CH
)
i
( 3 (D)
HOH
/
O
Ag
)
iii
(
N
CH
)
ii
(
SOCl
)
i
(
2
2
2
2


 
 (C)
Q.9 Write themost probable product ofthe following reaction


 

ONa
CH3 Product [Ans. ]
Q.10 Purposemechanismforfollowing conversion.
O
H
)
ii
(
MgBr
CH
)
i
(
2
3



 

Q.11 Complete.
(i) A
OH
CH
)
OH
(
CH
CH
HO 4
KHSO
2
2



 




 (ii)



 
 4
KHSO
B

3. ORGANICCHEMISTRY
Daily Practice Problems
Time : 30 Min. Max. Marks: 27
Q.1 Ei


Whichofthe following product cannot be obtained bythis reaction. [2]
(A) (B) (C) (D*)
Q.2 CH2 = C = O
)
equi
2
(
MgBr
CH
)
ii
(
Br
)
i
(
3
2


 
 C4H8O [2]
(A*) (B) (C) (D)Allofthese
Q.3alkene
4
2
CCl
Br



Br
Br
|
|
COOH
CH
CH
HOOC 

 (X) [2]
4
2
CCl
Br



Br
Br
|
|
COOH
CH
CH
HOOC 

 (Y)
The correct statement with respect to above reactions are
(A*) The reactionis stereospecific
(B*) (X) is erythro and (Y) is threo isomer
(C) (X) is threo and (Y) is erythro isomer
(D) eachgives mixture of(X)and (Y)
Q.4alkene Which is B in the sequence 
 

HBr A
A
O
H
/
CO
)
ii
(
ether
/
Mg
)
i
(
3
2




 
 B [2]
(A) (B*) (C) (D)
Q.5 IdentifyA, B and C and give their structures. [3]
CLASS : XII (ALL) DPP. NO.- 23

4. Q.6alkene Give mechanismfor givenreaction: [4]


 


HOH
/
H
-Terpeniol
[Ans. 


H  

 


H
/
HOH ]
Q.7 Draw the structures ofstable configuration obtained after acidic hydration ofthe following unsaturated
compounds: (exclude rearranged products) [4]
(I) (II) (III) (IV)
[Ans. (I) (II) (III) (IV) ]
Q.8 Formulatemechanisms forthe following transformations. [4]


 
 2
2N
CH
[Sol.
]

5. ORGANICCHEMISTRY
Daily Practice Problems
Time : 45 Min. Max. Marks : 42
Q.1elimination
3
2
2
2
2
3
3
CH
|
OH
CCH
CH
CH
CH
CH
|
CH




 
 4
2SO
H
.
conc
Major product is: [2]
(A*) CH3
CH2
CH2
CH2
CH= (B)
3
2
2
2
2
3
2
CH
CH
|
C
CH
CH
CH
CH
|
|
CH
(C)
3
2
2
2
3
CH
|
C
CH
CH
CH
CH  (D)
3
3
2
2
2
3
CH
|
CH
CH
C
CH
CH
CH
CH 

Q.2 Me2CDOH is oxidised byH2CrO4/aq. acetoneat about 1/7th the rateofeither Me2CH(OH) or (CD3)2
CHOH – explain. [2]
[Sol. Because ofBond Energyof ]
Q.3
ether
dry
LAH

 
 A
A 
 
 3
PBr
B 



 

KOH
Alcoholic
C
What are Ato C ? [3]
[Sol. (A) (B) (C) ]
Q.4alkene AssignAto D in the given reaction sequence [4]





 

,
AgOH
)
ii
(
)
excess
(
I
CH
)
i
( 3
A
A





 

,
AgOH
)
ii
(
)
excess
(
I
CH
)
i
( 3
B
[Sol. A = B = MeOH ]
Q.5 How willyou convert cyclohexane into benzeneinfour steps. [3]
[Sol.




h
Br2 

 
 KOH
alc
excess
NBS

 
 

 
 KOH
alc ]
CLASS : XII (ALL) DPP. NO.- 24

6. Q.6 PhOCH2Cl + Ph3P + tBuO—K+  A (C25H21P) [3]
A + ethyl methyl ketone  Ph3P = O + B (C11H14O)
B + dilute aqueous acid  C (C5H10O)
What are Ato C?
[Sol. A = Ph3P = CHOPh B = C =
3
5
2
CH
|
H
C
CH
H
C
|
|
O


 ]
Q.7 Completethefollowing reactions.
(a) + PPh3  A + B
(b) ClCH2COMe 
 

P
Ph3 A 


 

EtOH
EtONa B [4]
[Sol. (a) A = CH2 = CHMe + Ph3P = O = B
(b) A =

Cl
)
COMe
CH
P
Ph
( 2
3

B = CHC–Me ]
Q.8 Completethefollowing reactions.
(i) PhCH=CHCH2PPh3
+Cl— 
 
EtOLi
A 

 

PhCHO
B + C
(ii) Ph3P + (i) ClCH2COMe  D 

 
 3
2CO
Na
E 

 

PhCHO
F.
. [6]
[Sol. (i) A = PhCH = CHCH2= PPh3
B = Ph–CH=CH–CH=CH–Ph
C = Ph3PO
(ii) D = -
Cl
COMe
CH
P
Ph )
( 2
3

E = Ph3P = CHCOMe
F = Ph–CH=CHCOMe ]
Q.9 Give structure ofAto J. [9]


 

reduction
A(C9H17ON, an alcohol)
A + heat  B (C9H15N)
B + CH3I + Ag2O  C (C10H19ON)
C + heat  D (C10H17N)
D + CH3I + Ag2O  E (C11H21ON)
E + heat  F (C8H10)
F + Br2  G (C8H10Br2) [Thermodynamicallycontrolled pot]
G + Me2NH  H (C12H22N2)
H + MeI + Ag2O  I (C14H30O2N2)
I + heat  J (C8H8)
[Sol. (A) (B) (C) (D)

7. (E) (F) (G) (H)
(I) ]
Q.10 (a) Completethefollowing reactions: [6]
(i) Ph3P + CHCl3 


 



 K
BuO
t
A
(ii) PhCO(CH2)4Br 
 

P
Ph3
B
EtOH
Na
EtO


 



3
3
2 PPh
CH
)
CH
(
C
Ph
|
|
O



  C + D.
(b) Rate law for substitutionreactionof2-bromobutnae with

OH in75% ethanol& 25% water at
30°C is rate = 3.20 × 10–5 (2-bromobutane) (OH–) + 1.5 × 10–6 (2-bromobutane) what
percent of reaction take place by SN2 when [OH–] = 1.00 m.
[Sol. (a) A = Ph3P = CCl2 , B =




 Br
Ph
P
CH
C
Ph
O
3
4
2 )
(
|
|
, C = , D = Ph3P =O
(b) % by 2
N
S =
1
2
2
N
N
N
S
S
S

× 100
=
e]
Bromobutan
2
[
10
5
.
1
]
00
.
1
e][
bromobutan
2
[
10
20
.
3
100
]
00
.
1
e][
bromobutan
2
[
10
20
.
3
6
5
5











= 5
5
10
15
.
0
10
20
.
3
10
20
.
3
5






 × 100 = 96% ]

8. ORGANICCHEMISTRY
Daily Practice Problems
Time : 35 Min. Max. Marks: 31
Q.1 Which alkylhalide would you expect to react more rapidlybyan SN2 mechanism? [5]
(a) CH3CH2CH2Br or (CH3)2CHBr
(b) CH3CH2CH2CH2Cl or CH3CH2CH2CH2I
(c) (CH3)2CHCH2Cl or CH3CH2CH2CH2Cl
(d) (CH3)2CHCH2CH2Cl or CH3CH2CH(CH3)CH2Cl
(e) C6H5Br or CH3CH2CH2CH2CH2CH2Cl
[Ans. a1, b2, c2, d1, e2]
Q.2 Which SN2 reactionof each pair would you expect to take place more rapidlyina protic solvent?
[4]
(a) (1) CH3CH2CH2Cl + CH3CH2O– — CH3CH2CH2OCH2CH3 + Cl–
OR
(2) CH3CH2CH2Cl + CH3CH2OH — CH3CH2CH2OCH2CH3 + HCl
(b) (1) CH3CH2CH2Cl + CH3CH2O– — CH3CH2CH2OCH2CH3 + Cl–
OR
(2) CH3CH2CH2Cl + CH3CH2S– — CH3CH2CH2SCH2CH3 + Cl–
(c) (1) CH3CH2CH2Br + (C6H5)3N — CH3CH2CH2N(C6H5)3
+ + Br–
OR
(2) CH3CH2CH2Br + (C6H5)3P— CH3CH2CH2P(C6H5)3
+ + Br–
(d) (1) CH3CH2CH2Br(1.0M) + CH3O–(1.0M) — CH3CH2CH2OCH3 + Br–
OR
(2) CH3CH2CH2Br(1.0M) + CH3O–(2.0M) — CH3CH2CH2OCH3 + Br–
[Ans. a1, b2, c2, d2]
Q.3 Which SN1 reactionofeach pair would you expect to take place more rapidly? Explainyour answer.
[5]
(a) (1) (CH3)3CCl + H2O — (CH3)3COH + HCl
OR
(2) (CH3)3CBr + H2O — (CH3)3COH + HBr
(b) (1) (CH3)3CCl + H2O — (CH3)3COH + HCl
OR
(2) (CH3)3CCl + CH3CH2OH — (CH3)3COCH2CH3 + HCl
(c) (1) (CH3)3CCl(1.0M) + CH3CH2O–(1.0M) 
 

EtOH (CH3)3COCH2CH3 + Cl–
OR
(2) (CH3)3CCl(2.0M) + CH3CH2O–(1.0M) 
 

EtOH (CH3)3COCH2CH3 + Cl–
(d) (1) (CH3)3CCl(1.0M) + CH3CH2O–(1.0M) 
 

EtOH (CH3)3COCH2CH3 + Cl–
CLASS : XII (ALL) DPP. NO.- 25

9. OR
(2) (CH3)3CCl(1.0M) + CH3CH2O–(2.0M) 
 

EtOH (CH3)3COCH2CH3 + Cl–
(e) (1) (CH3)3CCl + H2O — (CH3)3COH + HCl
OR
(2) C6H5Cl + H2O — C6H5OH + HCl
[Ans. a2, b1, c2, d same, e1]
Q.4 Discuss the typeofisomerismexhibited bythe following pairs: [4] (a)
and
(b) and
(c) and
(d) and
[Ans. (a) Bothare similar structures, (b) Theyare positionalisomers, (c) Theyare enantiomers, (d) They are
constitutionalisomers]
Q.5 Give thefollowing equations and comment where necessary. [4]
(i) ClCH2CO2Et 


 


H
)
ii
(
,
O
Et
)
i
(
RMgX
2
2
? (ii) nC4H9MgBr + ? 



 


H
)
ii
(
,
O
Et
)
i
( 2
nC7H15OH
Q.6 Give product(s)ineachofthefollowing reactions [4]
(a) CH3 –
3
CH
|
CH – CH2 – CH2– CH3 

 

hv
/
Br2 (A)
(b) + NBS 


 

O
)
CO
H
C
( 2
5
6
(B)
(c) CH3 – CH2 – CH = CH2 + (CH3)3 – C – O – Cl 

hv
(C) + (D)
(d) C6H5 – CH2 – CH2 – CH3




 





3
3
3
CH
|
/
Cl
O
C
CH
|
CH
(E)

10. [Sol.(a)A:
3
3
2
2
3
CH
|
CH
CH
CH
C
CH
|
Br

 (b) B:
(c) C:
Cl
|
CH
CH
CH
CH 2
3 

 D: Cl
CH
CH
CH
CH 2
3 


(d)E:
Q.7 A concentrated aqueous solution of HBr reacts with EtOH to give EtBr but a concentrated aquous
solutionofNaBrdoes not – explain. [2]
[Sol. Poor LG -OH cannot directlysubstituted by ]
Q.8 Oxirane (epoxyethane) whenreacts withDMSO hydroxycarbonylcompound is formed as product
– explainwithmechanism. [3]
[Sol.

H
|
OH
CH
C
O 2


 + (CH3)2S]
Note:— Consider the following list provided below inplace ofthe list ofquestions given to you at the
end of DPP - 22 (dt. 21-22/08/06) of HALOGEN DERIVATIVES sheet. Solve it by
16th Sept. 2006
Exercise I(A) – Q.1 to Q.38
Exercise I(B)– Full
Exercise II– 1 to 29
Exercise IV(A)– Q.1 to Q.4, Q.6 to Q.9, Q.11, Q.13 & Q.14
Exercise IV(B)– Q.1 to Q.7