Test: Previous Year Questions) - (Level 1) - Hydrocarbons


24 Questions MCQ Test Chemistry Class 11 | Test: Previous Year Questions) - (Level 1) - Hydrocarbons


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This mock test of Test: Previous Year Questions) - (Level 1) - Hydrocarbons for Class 11 helps you for every Class 11 entrance exam. This contains 24 Multiple Choice Questions for Class 11 Test: Previous Year Questions) - (Level 1) - Hydrocarbons (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Previous Year Questions) - (Level 1) - Hydrocarbons quiz give you a good mix of easy questions and tough questions. Class 11 students definitely take this Test: Previous Year Questions) - (Level 1) - Hydrocarbons exercise for a better result in the exam. You can find other Test: Previous Year Questions) - (Level 1) - Hydrocarbons extra questions, long questions & short questions for Class 11 on EduRev as well by searching above.
QUESTION: 1

The compound 

product,

here product is               

[AIEEE-2002]

Solution:

The correct answer is option B

QUESTION: 2

Reaction
+ HOCl → product,

here product will be -                     

[AIEEE-2002]

Solution:

In HOCl, Cl acts as a cation and OH acts as an anion. First Cl+ attacks the aleke to form an electron deficient species(dueto repulsion, OH- can’t attack). Then OH- attacks to form compound a.

QUESTION: 3

Acetylene does not react with -

 [AIEEE-2002]

Solution:

The correct answer is option B
Acetylene does not react with NaOH because the product will be stronger acid H2​O and the stronger basic salt (CH≡CNa+)
Formation of a strong acid is not possible in acid-base neutralisation reaction of a weak acid. Hence, acetylene will not react with NaOH.
 

QUESTION: 4

On mixing a certain alkane with chlorine and irradiating it with ultraviolet light, it forms only one monochloroalkane. This alkane could be - 

 [AIEEE-2003]

Solution:

The number of monohalogenation products obtained from any alkane depends upon the number of different types of hydrogen it contains. Compound containing one type of hydrogen gives only one monohalogen product.

Out of the options, neopentane has only one type of hydrogen.

QUESTION: 5

Butene-1 may be converted to butane by reaction with –  

[AIEEE-2003]

Solution:

Alkenes can be converted to alkanes by addition of hydrogen (H2). In a hydrogenation reaction, two hydrogen atoms are added across the double bond of an alkene, resulting in a saturated alkane. The reaction occurs in the presence of a catalyst like nickel, platinum or palladium.

The correct option is B.

QUESTION: 6

During dehydration of alcohols to alkenes by heating with conc. H2SO4 the initiation step is- 

[AIEEE-2003]

Solution:

Dehydration of alcohol to alkene in presence of concentrated H2SO4 involves the –OH group in the alcohol that donates two electrons to H+ from the acid reagent, forming an alkyloxonium ion. The deprotonated acid (the nucleophile) then attacks the hydrogen adjacent to the carbocation and form a double bond.

Thus, the initiation step is protonation of alcohol.

The correct option is C.

QUESTION: 7

Bottles containing C6H5I and C6H5CH2I lost their original labels. They were labelled A and B for testing. A and B were separately taken in test tubes and boiled with NaOH solution. The end solution in each tube was made acidic with dilute HNO3 and then some AgNO3 solution was added. Substance B gave a yellow precipitate.
Which one of the following statements is true for this experiment ?  

[AIEEE-2003]

Solution:

QUESTION: 8

Which one of the following has the minimum boiling point?  

[AIEEE-2004]

Solution:

Isobutene (H3C)2 - C=CH2 has the minimum force of attraction (due to steric hindrance).Thus minimum boiling point.

QUESTION: 9

Amongst the following compounds, the optically active alkane having lowest molecular mass is -  

[AIEEE-2004]

Solution:

QUESTION: 10

Reaction of one molecule of HBr with one molecule of 1,3–butadiene at 40ºC given predominantly

[AIEEE-2005]

Solution:

The correct answer is Option A.

Under mild conditions (temperature ≈ - 80°C) kinetic product is the 1, 2-addition product and under vigorous conditions. (temp. ≈ 40°C) thermodynamic product is the 1 , 4-addition product. Thus, 1-bromo -2 - butene is the major product under given condition.

QUESTION: 11

Acid catalyzed hydration of alkenes except ethene leads to the formation of –   

[AIEEE-2005]

Solution:

QUESTION: 12

Alkyl halides react with dialkyl copper reagents to give  

[AIEEE-2005]

Solution:

The correct answer is option D
Alkyl halides react with dialkyl copper reagents to give alkanes. The reaction is called Corey House synthesis.
R2​CuLi+R′X→R−R′+RCu + LiX
For example, ethyl iodide reacts with lithium diethyl cuprate to form butane.
(C2​H5​)2​CuLi+C2​H5​−I→C2​H5​−C2​H5​+C2​H5​Cu + LiI

QUESTION: 13

Elimination of bromine from 2–bromobutane results in the formation of –

[AIEEE-2005]

Solution:


In elimination reaction of alkyl halide major product is obtained according to Saytzeff’s rule, which states that when two alkenes may be formed, the alkene which is most substituted one predominates.

QUESTION: 14

The alkene formed as a major product in the above elimination reaction is                

[AIEEE 2006]

Solution:

The given compound is the result of Hofmann Exhaustive Methylation reaction.
According to Hofmann Rule the less substituted alkene is the major product.


Hence CH2 = CH2 will be the major product with

QUESTION: 15

Fluorobenzene (C6H5F) can be synthesized in the laboratory -

[AIEEE 2006]

Solution:

From aniline by diazotisation followed by heating the diazonium salt with HBF4

QUESTION: 16

Phenyl magnesium bromide reacts with methanol to give -   

[AIEEE 2006]

Solution:

The reaction of methanol with phenyl magnesium bromide is:

CH3OH + C6H5MgBr → C6H6 + Mg(OCH3)Br

A mixture of benzene and Mg(OMe)Br is obtained.

The correct option is A.

QUESTION: 17

Which of the following reactions will yield 2, 2 - dibromopropane? 

[AIEEE 2007]

Solution:

The correct answer is option  A
Reaction of propyne with 2 molecules of HBr to form 2,2 -dibromine propane can be written as:
CH3 − C ≡ CH + 2HBr → CH3​ − C(Br) = CH2​
CH3​ − C(Br) = CH2​ + HBr → CH3​ − C(Br)2​ − CH3​
The reaction follows Markownikoff's rule.

QUESTION: 18

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

The compound B is  

[AIEEE 2008]

Solution:

The correct answer is option C

QUESTION: 19

The treatment of CH3MgX with produces   

[AIEEE 2008]

Solution:

Here, Grignard reagent acts as base and acid base reaction occurs (as hydrogen of sp hybridized C atom acts as acid). So CH3- takes H+ and forms CH4.

QUESTION: 20

The hydrocarbon which can react with sodium in liquid ammonia is -  

[AIEEE 2008]

Solution:

The correct answer is option  A
1-butyne can react with sodium in liquid ammonia. Because terminal alkynes have acidic hydrogen. This acidic hydrogen can replace Na in presence of liquid ammonia.

 

QUESTION: 21

Ozonolysis of an organic compounds gives formaldehyde as one of the products. This confirms the presence of :

  [AIEEE 2011]

Solution:


Presence of one vinyl group gives formaldehyde as one of the product in ozonolysis.

QUESTION: 22

Ozonolysis of an organic compound ‘A’ produces acetone and propionaldehyde in equimolar mixture. Identify ‘A’ from the following compounds : 

[AIEEE 2011]

Solution:

Ozonolysis breaks the double bond and oxidizes that carbon. To solve these questions, when the reactants are asked, just remove the carbonyl oxygen from the products and join the resulting compounds using a double bond. 

QUESTION: 23

2-Hexyne gives trans -2- Hexene on treatment with - 

[AIEEE 2012]

Solution:

The correct answer is option A
2-hexyne with Li/NH3​ gives trans-2-hexene. This reaction is also considered as Birch reduction.

QUESTION: 24

Which branched chain isomer of the hydrocarbon with molecular mass 72u gives only one isomer of mono substituted alkyl halide ? 

[AIEEE 2012]

Solution: