Organization Panel

Add Question Remove Question View Key View Solution View Paper 2 Column

Paper Set 1 Paper Set 2 Paper Set 3 Paper Set 4

	QPID #4779 (SET 3)		CHEMISTRY KCET- DPP 04 Subjective
Class/Batch: KCET Crash	Duration: 60 min	Date: 03 Apr,2023	Total Mark:60

Instructions: KCET Crash

CHEMISTRY: Hydrocarbons-Alkenes, Hydrocarbons-Alkynes, HYDROCARBONS,

Section 1 (CHEMISTRY) 60X1=60

#150940

Mark error

Following compound is treated with NBS Compound formed A is

Solution:

#151272

Mark error

Which of the following has highest knocking?

1)
Olefins
2)
Branched chain olefins
3)
Straight chain olefins
4)
Aromatic hydrocarbons

Solution:
Straight chain olefins

#151382

Mark error

$C{H_3} - C \equiv C - C{H_3}\xrightarrow{{Lindlar's\,Catalyst}}$A the compound 𝐴 is

1)
𝑐𝑖𝑠-2-butene
2)
𝑡𝑟𝑎𝑛𝑠-2-butene
3)
𝑖𝑠𝑜-butene
4)
1-butene

Solution:
𝑖𝑠𝑜-butene

#157736

Mark error

The correct order for acid strength of compounds $CH \equiv CH,C{H_3} - C \equiv CH\,and\,C{H_2} = C{H_2}$

1)
$CH = CH > C{H_2} = C{H_2} > C{H_3} - C = CH$
2)
$HC \equiv CH > C{H_3} - C \equiv CH > C{H_2} = C{H_2}$
3)
$C{H_3} - C \equiv CH > C{H_2} = C{H_2} > HC \equiv CH$
4)
$C{H_2} - C \equiv CH > CH = CH > CH2 = C{H_2}$

Solution:
$CH = CH > C{H_3} - C = CH > C{H_2} = C{H_2}$ (Acidic strength order)

#162334

Mark error

Acetylene and Benzene are distinguished by

1)
H₂ / Ni
2)
Bayer’s reagent
3)
Tollen’s reagent
4)
either (2) or (3)

Solution:
Acidic hydrogens

#190675

Mark error

Solution:

#191661

Mark error

$CH \equiv CH\xrightarrow[{\left( {Excess} \right)}]{{Na}}X\xrightarrow[{Excess}]{{{C_2}{H_5}Cl}}'Y'.$ Monochlorination of ‘Y’ [Using UV light] gives____number of isomeric products

1)
3
2)
6
3)
8
4)
12

Solution:

#2580116

Mark error

Geometrical isomerism is not shown by

1)
2)
3)
CH₂ = C(Cl)CH₃
4)
CH₃ - CH = CH -CH = CH₂

Solution:
The condition for geometrical isomerism is

#2580132

Mark error

By which reaction ethene is obtained from ethyne -

1)
oxidation
2)
polymerisation
3)
hydrogenation
4)
dehydrogenation

Solution:
hydrogenation

10)

#2580136

Mark error

Ethyl alcohol is heated with conc. H₂SO₄. The product formed is :

1)
2)
C₂H₆
3)
C₂H₄
4)
C₂H₂

Solution:
C₂H ₅OH $\to_{K M n O_{4}}^{c o n c . H_{2} S O_{4}}$ C₂ H₄ + H₂O

Note : If ethyl alcohol is taken in excess and the reaction is carried out at a temperature of 433-443 K diethyl ether is formed.

2C₂ H₅ OH $\to_{433 - 443 K}^{c o n c . H_{2} S O_{4}}$ C₂H₅OC₂H₅ +H₂O

11)

#2580151

Mark error

When hydrochloric acid gas is treated with propene in presence of benzoyl peroxide, it gives

1)
2-Chloropropane
2)
Allyl chloride
3)
No reaction
4)
n-Propyl chloride.

Solution:
Peroxide effect is observed only in case of HBr. Therefore, addition of HCl to propene even in the presence of benzyoyl peroxide occurs according to
Markovnikov’s rule :

CH₃- CH= CH_{2 $\to_{{(C_{6} H_{5} C O)}_{2} O_{2}}^{H c l}$}CH₃ - CHCl - CH₃

12)

#2580166

Mark error

Solution:
We know that in case of an unsymmetrical alkene there is the possibility of forming two products. In such cases the formation of major product is decided on the
basis of Markownikoffs rule which is rationalized in terms of stability of the intermediate carbocation. Also remember that 3° carbocation is more stable than 2°
carbocation and 2° carbocation is more stable than 1° carbocation.

of the two possibilities 2° carbocation is more stable so the product of the reaction expected was predominantly one formed by 2° carbocation i.e.

i.e. 2– Bromo-3-Methylbutane
However some electrophilic addition reaction form products that are clearly not the result of the addition of electrophile to the sp2 carbon bonded to the most
hydrogens and the addition of a nucleophile to the other sp2 carbon. In the above cases the addition of HBr to 3-methyl-1- butene the two products formed are shown below.

In this case the major product formed is 2- Bromo-2- methylbutane i.e. option (b) is correct answer. (Note: The unexpected product results from a
rearrangement of carbocation intermediate. Please note that all carbocation do not rearrange

13)

#2580172

Mark error

Alkenes usually show which type of reaction –

1)
addition
2)
substitution
3)
elimination
4)
superposition

Solution:
Alkenes are unsaturated hydrocarbon having double bond so generally gives addition reaction.

14)

#2580178

Mark error

In the given reaction

CH₃CH₂CH = CHCH_{3 $\overset{X}{\to}$}CH₃CH₂COOH +CH₃COOH

The X is

1)
C₂H₅ONa
2)
Conc. HCl +Anhy.ZnCl₂
3)
Anh. AlCl₃
4)
KMnO₄/OH–

Solution:
A doubly bonded carbon atom having an alkyl group is oxidised to aldehyde which is further oxidised to carboxylic acid

15)

#2580208

Mark error

Which of the following compounds does not follow Markownikoff’s law ?

1)
CH₃CH = CH₂
2)
CH₂CHCl
3)
CH₃CH = CHCH₃
4)
None of these

Solution:
As per Markovnikoff’s law, the positive part (e.g. Hof HX) or the less negative part of the reagent adds to that carbon atom of alkene which has more
number of hydrogen atoms (the rich gets richer). So (c) is the correct option as the two carbons containing the double bond have one H atom each
i.e. symmetric

16)

#2580226

Mark error

Ethylene reacts with alkaline KMnO₄ to form

1)
Oxalic acid
2)
HCHO
3)
Ethyl alcohol
4)
Glycol

Solution:

17)

#2580255

Mark error

An alkyne has general formula :

1)
C_nH_2n
2)
C_nH_2n+1
3)
C_nH_2n+2
4)
C_nH_2n-2

Solution:
General formula for alkynes is C_nH_2n–2

18)

#2580266

Mark error

The IUPAC name of the compound having the formula CH $\equiv$ C – CH = CH₂ is :

1)
1-butyn-3-ene
2)
but-1-yne-3-ene
3)
1-butene-3-yne
4)
3-butene-1-yne

Solution:
If both the double and triple bonds are present, the compound is regarded as derivative of alkyne. Further if double and triple bonds are at equidistance from
either side, the preference is given to double bond

19)

#2580284

Mark error

Maximum carbon-carbon bond distance is found in –

1)
ethyne
2)
ethene
3)
ethane
4)
benzene

Solution:
In C₂H₆, C – C bond length is 1.54 Å.

20)

#2580313

Mark error

The correct order towards bond length is

1)
C - C < C = C < C $\equiv$ C
2)
C $\equiv$ C < C = C < C - C
3)
C = C < C $\equiv$ C < C - C
4)
C = C < C - C < C $\equiv$ C

Solution:

21)

#2580339

Mark error

Calcium carbide when treated with water gives :

1)
ethylene
2)
methane
3)
acetylene
4)
ethane

Solution:

22)

#2580354

Mark error

The hydrocarbon which can react with sodium in liquid ammonia is

1)
CH₃CH₂CH₂C $\equiv$ CCH₂CH₂CH₃
2)
CH₃CH₂C $\equiv$ CH
3)
C_H3CH = CHCH₃
4)
CH₃CH₂C $\equiv$ CCH₂CH₃

Solution:
Alkynes having terminal –C $\equiv$ H react with Na in liquid ammonia to yield H₂ gas. CH₃CH₂C $\equiv$ CH can react with Na in liquid NH₃ so the correct answer is (b).

CH₃CH₂ C $\equiv$ CH $\to_{l i q u i d N H_{3}}^{N a i n}$

$C H_{3} C H_{2} C \equiv C^{-} N a^{+} + \frac{1}{2} H_{2} (g)$

23)

#2580373

Mark error

What happens when a mixture of acetylene and hydrogen is passed over heated Lindlar’s catalyst ?

1)
Ethane and water are formed
2)
Ethylene is formed
3)
Acetylene and ethane are formed
4)
None of these

Solution:

24)

#2580394

Mark error

1)
HBr, Br₂, CH₃COCH_3, CH₃CHO
2)
Br₂, HBr, CH₃COCH₃, CH₃CHO
3)
HBr, HBr, C_H3COCH_3, CH₃CHO
4)
Br₂, HBr, CH₃CH₂CHO, CH₃CHO

Solution:
Br₂, HBr, CH₃COCH₃, CH₃CHO

25)

#2580413

Mark error

The ring structure of benzene was proposed by

1)
Faraday
2)
Davy
3)
Kekule
4)
Wohler

Solution:
Kekule in 1865 suggested a ring structure of benzene in which the ring was composed of six carbon atoms, each of which carries one atom of hydrogen. To satisfy
the fourth valency of the carbon atom, he suggested three alternate double bonds.

26)

#2580431

Mark error

The chemical system that is non-aromatic is

Solution:

27)

#2580445

Mark error

Solution:
–NO₂ is a meta-directing group. As it is also a deactivating group so no chance of introduction of second –Br atom

28)

#2580464

Mark error

The strongest ortho - para and strongest meta - directing groups respectively are

1)
–NO₂ and –NH₂
2)
–CONH₂ and –NH₂
3)
–NH₂ and –CONH₂
4)
–NH₂and –NO₂

Solution:
–NH₂and –NO₂

29)

#2580494

Mark error

Benzene reacts with CH₃COCl + AlCl₃ to give

1)
chlorobenzene
2)
toluene
3)
benzyl chloride
4)
acetophenone

Solution:
acetophenone

30)

#2580503

Mark error

AlCl₃acts as ________ in Friedel-Crafts reaction

1)
nucleophile
2)
electrophile
3)
free radical
4)
intermediate

Solution:
Friedel- Craft reaction occurs in presence of an attacking reagent which is an electrophile (AlCl₃).

31)

#151213

Mark error

Cyclohexene on reaction with OsO₄ followed by reaction with NaHSO₃ gives

1)
𝑐𝑖𝑠 − diol
2)
𝑡𝑟𝑎𝑛𝑠 − diol
3)
Epoxy
4)
Alcohol

Solution:
𝑐𝑖𝑠 − diol

32)

#151363

Mark error

The treatment of 𝑅′ Mg𝑋 with 𝑅C ≡ CH produces

1)
RH
2)
R'H
3)
R - R
4)
R - R'

Solution:
R'H

33)

#151541

Mark error

Degree of unsaturation in the following compound is

1)
1°
2)
2°
3)
3°
4)
4°

Solution:
Degree of instauration=; $\frac{{2{n_1} + 2 - {n_2}}}{2}$where, 𝑛₁ is the number of carbon atoms and 𝑛₂ the number of hydrogen atoms.

In compound Number of carbon atoms =8
Number of hydrogen atoms=12 Degree of unsaturation= $\frac{{2 \times 8 + 2 - 12}}{2} = 3$

34)

#160023

Mark error

Propyne and propene can be distinguished by

1)
Conc. H₂SO₄
2)
Br₂ in CCl₄
3)
Dil KMnO₄
4)
AgNO₃ in ammonia

Solution:
AgNO₃ in ammonia

35)

#188990

Mark error

Which of following doesnot react with Tollen's reagent?

Solution:
has no acidic hydrogens

36)

#191019

Mark error

Solution:

37)

#196218

Mark error

Which of the following have maximum heat of hydrogenation :

Solution:

38)

#2580118

Mark error

Hex-2-ene and 2-methylpent-2-ene exhibit

1)
chain isomerism
2)
position isomerism
3)
geometrical isomerism
4)
optical isomerism

Solution:
chain isomerism

39)

#2580133

Mark error

The major product formed when 2-bromobutane is treated with alcoholic KOH is

1)
2-Butanol
2)
1-Butene
3)
1-Butanol
4)
Trans-2-butene

Solution:

40)

#2580149

Mark error

Paraffins are soluble in

1)
Distilled water
2)
Benzene
3)
Methanol
4)
Sea water

Solution:
Paraffins or alkanes are non-polar compounds. Hence soluble in benzene

41)

#2580153

Mark error

When one mole of an alkene on ozonolysis produces 2 moles of propanone, the alkene is

1)
3-methyl-1-butene
2)
2, 3-dimethyl-1-butene
3)
2, 3-dimethyl-2-pentene
4)
2, 3-dimethyl-2-butene

Solution:
Since given alkene on ozonolysis gives 2 moles of propanone hence alkene should have a double bond between two equivalent C atoms i.e. the formula should be

42)

#2580168

Mark error

Butene-1 may be converted to butane by reaction with

1)
Sn – HCl
2)
Zn – Hg
3)
Pd/H2
4)
Zn – HCl

Solution:
Alkenes combine with hydrogen under pressure and in presence of a catalyst (Ni, Pt or Pd) and form alkanes.
Butene - 1 $\overset{H_{} / p d}{\to}$ Butane

43)

#2580174

Mark error

A reagent used to test unsaturation in alkene is -

1)
ammonical Cu₂Cl₂
2)
ammonical AgNO₃
3)
solution of Br₂ in CCl₄
4)
conc. H₂SO₄

Solution:
solution of Br₂ in CCl₄

44)

#2580202

Mark error

The negative part of an addendum adds on to the carbon atom joined to the least number of hydrogen atoms. This statement is called

1)
Thiele’s theory
2)
Peroxide effect
3)
Markownikoff’s rule
4)
Baeyer’s strain theory

Solution:
According to Markownikoff’s rule, "in case of addition of an unsymmetrical reagent (H– X), the positive part get attached to the C which is least substituted or
which bears larger number of hydrogen atoms."

Markownikoff’s rule is based on the stability of carbocations (3° > 2° > 1° > methyl).

45)

#2580215

Mark error

In the following sequence of reactions, the alkene affords the compound ‘B’

The compound B is

1)
CH₃CH₂CHO
2)
CH₃COCH₃
3)
CH₃CH₂COCH₃
4)
CH₃CHO

Solution:
Completing the sequence of given reactions,
CH3 – CH= CH- CH3 $\overset{O_{3}}{\to}$

Thus ‘B’ is CH₃CHO Hence (d) is correct answer

46)

#2580229

Mark error

The reaction of HI with CH3 – CH = CH2 at 400°C yields :

1)
CH₂ I – CH = CH₂
2)
CH₃ – CHI – CH₃
3)
CH₃ – CH₂ – CH₂ I
4)
CH₂I – CH₂ – CH₂I

Solution:
When unsymmetrical unsaturated hydrocarbon reacts with unsymmetrical reagent, then negative part of reagents attacks that carbon which has less H-atom.
[Markownikoff's rule]

47)

#2580261

Mark error

Number of alkynes for formula C₅H₈ is –

1)
2
2)
3
3)
4
4)
5

Solution:
Three alkynes are possible for the formula C₅H₈.
CH₃CH₂CH₂C $\equiv$ CH

48)

#2580276

Mark error

The C - H bond length is minimum in the bond formed by

1)
sp - s overlapping (as in alkynes)
2)
sp² – s overlapping (as in alkenes)
3)
sp³ – s overlapping (as in alkanes)
4)
None of these

Solution:
sp - s overlapping (as in alkynes)

49)

#2580298

Mark error

Butyne-2 contains :

1)
sp hybridised carbon atoms only
2)
sp³ hybridised carbon atoms only
3)
both sp and sp² hybridised carbon atoms
4)
both sp and sp³ hybridised carbon atoms

Solution:
We know that carbon having
(i) 4 $σ$ bonds correspond to sp^₃
(ii) 3 $σ$ and 1 $π$ bond correspond to sp²
(iii) 2 $σ$ and 2 $π$ bonds correspond to sp

Thus, butyne-2 has sp and sp³ hybridised carbon atoms

50)

#2580320

Mark error

Which C-atom is the most electronegative in this structure?

1)
I
2)
II
3)
III
4)
all are equal electronegative

Solution:
As the number of bonds between carbon atoms increases, electronegativity of that carbon also increases due to increasing active power of electrons.
Also sp hybrid is more electronegative than sp² which is more electronegative than sp³( s character decreases) Hence, option (a) is correct.

51)

#2580351

Mark error

Which of the following will be the final product when C₂H₂ reacts with HCl

1)
2)
3)
4)
None of these

Solution:
CH $\equiv$ CH+ HCl $\underset{}{\to}$ CH₂ = CH- Cl $\overset{H c l}{\to}$

52)

#2580363

Mark error

When propyne reacts with aqueous H₂SO₄ in the presence of HgSO₄, the major product is

1)
Propanal
2)
Propyl hydrogen sulphate
3)
Acetone
4)
Propanol

Solution:

53)

#2580383

Mark error

Which of the following reaction is shown by alkynes ?

1)
Addition
2)
Substitution
3)
Polymerization
4)
All of these

Solution:
Addition – CH $\equiv$ CH + 3H₂ $\overset{N i}{\to}$ CH₃ - CH₃

Substitution – CH $\equiv$ CH+ Na $\underset{}{\to}$ $C H \equiv C^{-} N a^{+} + \frac{1}{2} H_{2}$

Polymerization –

$3 C H \equiv C H \to_{p o l y m e r i z a t i o n}^{h o t c u t u b e} C_{6} H_{6} b e n z e n e$

54)

#2580403

Mark error

Which of the following catalyst is used for the following conversion ?

1)
Platinized Asbestos
2)
Red hot iron tube
3)
Platinized Nickel
4)
Iron-molybdenum

Solution:
Red hot iron tube

55)

#2580419

Mark error

The benzene molecule contains

1)
6 sp²hybrid carbons
2)
3 sp² hybrid carbons
3)
6 sp³ hybrid carbons
4)
3 sp³ hybrid carbons

Solution:
In the benzene molecule all the six carbons are sp2 hybridised as each C has one double bond.

56)

#2580436

Mark error

The product A is

1)
Benzene
2)
Benzaldehyde
3)
Toluene
4)
Benzoic acid

Solution:
This is an example of decarboxylation reaction

57)

#2580453

Mark error

Catalytic hydrogenation of benzene gives

1)
xylene
2)
cyclohexane
3)
benzoic acid
4)
toluene

Solution:

58)

#2580476

Mark error

Benzene can be obtained in the reaction

1)
Ethene + 1, 3-butadiene
2)
Trimerisation of ethyne
3)
Reduction of PhCHO
4)
All of these

Solution:
Benzene can be obtained by polymerisation of acetylene

59)

#2580498

Mark error

Benzene on reaction with ozone forms __________.

1)
2 molecules of aldehyde and 1 molecule of ketone
2)
2 molecules of ketone and 1 molecule of aldehyde
3)
triozonide
4)
hexaozonide

Solution:

60)

#2580513

Mark error

During the nitration of benzene. In the process of generation of nitronium ion sulphuric acid behaves as a/an ______ and nitric acid behave as a/an _________.

1)
base, acid
2)
acid, base
3)
strong acid, weak acid
4)
weak acid, strong acid

Solution:
In the process of generation of nitronium ion, sulphuric acid serves as an acid and nitric acid as a base.

QPID #4779 (SET 3)

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution:

Solution: