4A HYDROCARBONS (ALKANES)
1. On halogenation, an alkane gives only one monohalogenated product. The alkane may
be:
(a) 2-methyl butane (®) 2, 2-dimethyl propane
(©) cyclopentane (@) both () and (©)
2. Which of the following compounds can be best prepared by Wurtz-reaetion ?
@) Iso-butane (b) n-butane
(© npentane @ Iso-pentane
3. Ahydrocarbon A (V.D. = 36) forms only one monochloro substitution product. A will be :
(@) iso-pentane (©) neo-pentane
(© cyclohexane @) methyl-cyclohexane
4. Ethyl iodide and n-propyl iodide are allowed to undergo Wurtz reaction. The alkane which
will not be obtained in this reaction is :
(@) butane (©) propane
(© pentane @ hexane
5. CH,—CH —CH,—CH, 25
is
‘Number of chiral centers generated during monochilorination in the above reaction :
@1 m2 @3 @4 6. cH cH,
Above conversion canbe achieved by:
@ m/e Lin, 2
(© Mg / (ether) then H,0 @ all of these
7 Burne 22,
Give the tol numberof monochloro products (including stereoisomers), which ae possible
{nthe above reaction.
@2 o3 oF @s
8. cH, scl," aH,ci+ Hel
To obtain high yields of CHCl, the rato of CH, ro Cl, must be :
(@) high ) low
© equal (@ cant predicted
9. Double bond equivalent of exbane is:
Gabane
@a4 ms a6 @7
10. How many bond cleavages are required to convert cubane into non cyelic skeleton ?
a) 44
Gubane —-Non-eyclie skeleton
@2 3 oF @s
11. Drawan energy profile diagram fora three step reaction in which fist step is slowestand last
step is fastest. (Assume that reaction is exothermic)
| |
@ o
proees of reaction progres of reaction
|
© Ta (a) None of these 12.
14.
15.
16.
17.
Hy—cHcH, cH, S24 (@) = Number of monochloro product including
sta
3
@4 ms os @7
NDy—NDy
OA
Prout is
. D wD
@ © > @ (a) both () & Ce)
ys OL]
Double bond equivalent (degree of Unsaturaton) of (A) i:
@il &2 ©3 @4
Aang te fning lanes a ecrensg ore heres of onbusien
Hs
L
© an-foas icy gc, a,
oe pen emp 0
GiCH, — Gy — CHa = Gy — Cs
f@ @>@ > Go ©) Gi) > @> Go
@t>a>o @w>ad> a
Ws 1,
Cis a
Product ofthe above reaction willbe:
(@ Racer miarre (2) Diastereomers
© Meo (@) Constatonal isomers
CHy
»—|—
rc
CH,—CH,
Which of the following compound will nor be obtained as a product inthe above reaction ? 18.
19.
a1.
22.
23.
© cH, @
Following are the strucutes of fou isomer of hexane. Among the names given below, which
cortecdy identifies the fifth isomer ?
CH,CH,CH.CH.cH.CH, (CH,),CH
(Gi) ,CHCH.CH.CH, (Gii,),CHCH(CHS),
(a) 2-Methyl pentane () 2thyl butane
© 2,3-Dimethyl butane (@) 3 Methyl pentane
Which ofthe following describes the best relationship between the methyl groups in the
‘hair conformation ofthe substance shown below ?
Cis
CH,
(2) Trans ) Anti
(© Gauche (@ Ealipsea
‘Compare the stabilities ofthe following two compounds (A) and (8):
A /:cis-1-ethyl-3-methyl cyclohexane B :trans-1-ethyl3-methyl cyclohexane
(a) Ais more stable (@) Bismore stable
(© Aand Bare of equal stability (@) No comparison can be made
‘Which conformation of ethane has the lowest potential energy ?
(a) Eclipsed (b) Skew
(© Staggered (@) All will have equal povential energy
Ethane is subjected to combustion process. During the combustion the hybrid state of carbon
changes from :
@ gos" ©) 910 9
(© pt? © 9 wsp"
CH, —a, —cHh, Gy “sc, — Ga,
cay
[Above reaction isan example of = 24,
25.
26.
27.
29.
‘Which ofthe following has highest chlorine content ?
(@) Pyrene (@) DOT (© Chloral @ Gammaxene
pee
(@) Wurtz reaction (b) Kolbe electrolysis method
See ET
Soe :
ne ee
(@) C,H, (b) CaD, {© CafOD),, @ cD,
ena] ayo abo)
wrqames: tacts” “tages
9 : 2
Agi anette carci demi
‘Analkane (mol wt. = 86 on bromination gives ony ro monobromo derivatives excluding
stereoisomers). The alkane is : ¥ od
Gs
© CHy— GHC, C,H, 0) CHF aH, Ca,
CH; Gis
as
© a, ciara, @ Gi~¢—a,
cH, cH, i,
‘Order of the bond strength of C—H bonds involving
sp? >sp? 0) sp? >5p? >ap
© pos > (@) 59? >sp> 2p?
eee
‘Among the structures given , select the enantiomers :
(@) Land () Cand m
(© Wand mt (@ Land mt 32.
33.
34.
38.
36.
37.
@ ny am
‘The correct order of reactivity of, I & If towards addition reactions is:
@I>M>1 @i>usm — @m>u>1 — @M>1> 1
oe, ® 6
7
Product (A) of above reaction is :
DO +O #O
eof ha ems Ws hc pecan fst en ebay eng
fone step only?
@ H.C= cH, () CH,OH
© CH, —Br @ cH; —cH, —On
How many carbon atoms does an alkane (nota lealkane) need before its capable wo exist
@4 ws os @7
Angi long ral tonto aio lth nwhich habe the
‘major product —
CH_—CHy
o)-2 wey am, coo) 2
fre
one SoC AA Bs
@RARS OPRU —ORRST HEARST
+c, + monechor prodct
‘To maximise the yield of monochloro product in the above reaction ?
(0) ch mus beaded in exes
(b) Reactant (A) must be added in excess
{© Reaction must be cad oat in dark
(@ Reaction must be cried out with equimolar miu of Cy and A
CH, —CH, oi, i,
Major rodutinthe above eacion i:
(@ fecenie ure ©) Meso
(© Diastereomers (d) Constitutional isomers: 39.
41.
ORGANIC Chemisrfor IPIBE
"Sele the cain propagation steps in the fre radial chlorination of methane.
aa, 20" Gat +ciiy—> cna
@) ar +c, —> Hy +H @ HW +d,— Haar
© cH} +cl,—> cHa+cr
@2,3,5 13,6
35 234 7
ois
‘The number of possible monobromo products i (excluding stereoisomers)
@s os os @w
iy
on
+B
won
Ci, He
Be" will abstract which ofthe hydrogen mast readily?
@a > @c @a
Arrange the following compounds in decreasing order oftheir heats of combustion
Ye dh AY
Gy Oy cH, cH,
o @ i
@ @>a@>@ &) G> © > Gin
© Gi) > @> @ @> G> Gi
(iy CHC F
& a
‘Arrange the hydrogens 8 din decreasing order oftheir reactivities towards chlorination:
(@a>b>e>d () b>e>d>a
(© b>c>a>d @c>b>ard
(On catalytic reduction (H,/Pt) how many alkenes will give n-butane ?
@i m2
©3 4
(On catalytic eduction (H,/Pt) how many alkenes will give 2-methylbutane ?
@1 2
@3 @4 47.
49.
Qa
How many dichloro products are formed inthe above reaction (including stereoisomers)?
@s
m6
a @9
cH,—CH
e
D’
Product ofthe above reaction will be:
(@) Racemic mixture oy tases 8
Me (@ Consieuional isomers
PhCH, —GH—CH,
D
Product ofthe above reaction will be:
(@) Diastereomers () Racemie mixture
(©) Meso @ Constitutional isomers
cc
cus yee)
cy
Products coved a sore Worx masa:
0 GID» IS"
0 DW (© bona
cHy City
Rank the transition states that occur during the following reaction steps in order of
increasing stability (least > most stable):
1 H,¢-O#,—> CH +H,0
2 (CHty)9C-OH; —> (CH3)3C" +20
3. (GHs),CH-OH— (CHy),CH" + HO
@1<2<3 @2<3<1
@1<3<2 @2<1<3 ez ORGANIC Chemistry for ITE
50. Which of the following does not represent major product ofthat reaction?
a
Be
oo
a
be
Br
©
Bf 9
© <>
1 /@ © o ws |] >e|@ @
|_9. | w {10.| ©. co }33-} w | 14.| © [18.] @ | 16.| w |
Ia7.f@ [18 | @ [39.| © [20] w [21] @ [22] [23] @ 124] w |
| 25.| cj | 26.] @ [27] @ [28.[ @ | 29.] @ [30 @ [31] m [52.] w
| 33.| co [34] w [5.| w [26.| w [57.| w]36.| @ | 39-| o [40.| a
| 43. | @ | 42.| @ [43. © | 45.| © [46] @ [a7] @ [48.[ @
| 49.| @ | s0.| @ E For the given question (1, 2,3), consider the following reaction.
a +X, H + monohalogenation product
‘A. Lgheis involved in which step ofthe reaction:
(@) tnkiation only (©) Termination only
(© Propapation only (@) Propagation and Termination
3. Which halogen wil give the bes el of single monahalogenation product ?
@® wa, (0 Bey Ob
How many monohato derivatives are poste (excluding stereoisomers)?
3 os 5 @6
ae
“Halogenation is substitution reaction, where halogen replaces one or more hydrogens of
Ihydrocarbon.
R—H+X,—2 RX 10
verter el tome Stel
soe ici,
fected
|. | #
Leer :
'e Free radial
Ie ae + we
meuwe maa Foor Th alin
eta tian tonto der ont
Seoenreete eine pope nee cn
Chlorine free radical make 1, 2" 3° radicals with almost equal ease, whereas bromine free
radicals have a clear preference forthe formation of teary fee radials. So, bromine ts less
eacive, and more selective whereas chlorine is les selective and more reactive.
The relative rate of biraton of ydogen by Br
800) a”
The ne rtf aaron open
a8 a Consider the above argument and answer A to G:
‘A. Ishalo-2,3-dimethyl butane will be obtained in beter yields, if halogen is
@) Br, @) a, Ok (d) Can't be predicted
oy cr,
x
By
-A8S¢e product wil tse in beter yield if. is
@ oe OL (© Br, @ Can't be predicted
I
© CH,—CH—cH, 82, Product
‘Major product in the above reaction is:
Hy
way — bic,
L
a © cH Gacy,
a
© Gi, —ai, —cH, —a. @ cay
HCH, —CH,
1
D. Which ofthe following will give five monochloro products, when allowed to react with Cl; in
presence of sun light (excluding stereoisomers) ?
(@) pentane —(®) Ko-pentane (©) methyl: pentane (2) 3-methyl pentane
cH CH cH, cH
H I mu 1 1 "
Baty east —GH, ——+ GF — GH — © ay
cH, Hy Br
2. 25. Snel poe 6)
‘what isthe value of x (6 yield of produc)?
@) 18% (b) 82% © 90% @) 60%
F. Wher would be the product ratio x/y in the chlorination of propane ifall the hydrogen were
abstracted at equal rte ?
Chis — Cy — City “SEs Cs —CH— C+ Hh — tat,
wo ¢
3 . s °
1 a 3 1
@ ot ©? @}
How many dichloro products (including stereoisomers) formed when
Rnloropntane acs mil in presence of Wradiaten >“ ® "
@s 6 _ 7 @s Ou ipsa? (Al Product (A)is
8,-3.6
ST (Ay Produet(A)is :
>(a)
a: ac cae,
eon
(@ Meso compound. (Racine (2 Diseremers
3
I CO RAOH, C0,
pact, ton wee
prod 0
jo mco,t hc,
OH (6) Ph—cH,
‘Match the column I with column Tl and with column
@ 14
(@) Optically active
O
Pe OS coerin I cokinn orD
Mono-chloro produets_ | Monochloro products
compound (excluding Gadluding
stereoisomers) stereoisomerism)
@) | 1 | 1
oH, — GH at, CH,
e) ba a 2 oe 3° 2
Fats
!
fo) an—e-c—on do 3 ” 5
Cig CHty
fog Cs — Te — CH — OH, 4 @ 6 ORGANIC Chemistry for UTJEE
Rochloropentane —2
ative dichloro products (P)
‘S++ Optically active dichloro products (Q)
chlereburane —S++ Optically active d-chloroproduets (R)
Sum? -Q-Ris
8. Match the column I and II.
Reaction ‘ype of Reaction
@ i= ® Meso compound
oy
© ae @ Diascereomers
OH
© © Racemie 2
a Optically inactive due to absence
@ = ®
of chiral center [HYDROCARHONS (ALKANES)!
9. Match the column
Reaction Product
Hs ey
o — o ‘oa
ts |
» CO wae, || Se
rn |
|
Gis e
ie once be > |
% %
@ Po © »:
Saas
10. How many distinct monochlorinated products, (including stereoisomers) may be obtained
when the alkane shown below i heated in the presence of Cl?
@1
@2
©3 @s 6
How many distinct monochlorinated products, (including stereoisomers) may be obtained
‘when the alkane shown below is heated inthe presence of Cl ?
@2
@s ws os
14 188,
ORGANIC Chemistry for IT-JEE
12. Match the column
|) ‘Wurtz reaction ee
| dimerization product |
(| a1, -c © 5
() | ct, -cl+ cH, ~cH, -L_S > @ 6 |
CH, -Cl+CH, -CH, -C
|, m ha
)CHy ~CH, ~CH, ~Cl— 8
HC =GH-cH=GH-cH, -C
| | cH, cH, -a > @ 1
oH
as, Ha E> (9). 6) =total number of d-chloro product
(CH,—CH,—CH,—CHy_
HYDROCARBONS (ALKANES)!
$-2-chlore hexane
189
Sees
1
13.
A-aB-C-b
A-b;B-GC-aD
abe
-GE-GF-bG-e
a-q-x:b-s-2¢-p-wid-a-x
P+Q+R=10
a-gb-pie-nd=
-pib-se-qgd-
1s
