Q 1 :

Number of alkanes obtained on electrolysis of a mixture of CH3COONa and C2H5COONa is _________ .                  [2024]



(3)

     Kolbe's electrolysis of RCOO-Na+ gives R-R

     2RCOONa+2H2OelectrolysisR-R+2CO2+2NaOH+H2

     Thus electrolysis of mixture of CH3COONa and C2H5COONa gives three alkanes: CH3-CH3, C2H5-C2H5 and CH3-C2H5

 



Q 2 :

The incorrect statement regarding conformations of ethane is:                          [2024]

  • Ethane has infinite number of conformations.

     

  • The dihedral angle in staggered conformation is 60°.

     

  • Eclipsed conformation is the most stable conformation.

     

  • The conformations of ethane are inter-convertible to one-another.

     

(3)

 



Q 3 :

3-Methylhex-2-ene on reaction with HBr in presence of peroxide forms an addition product (A). The number of possible stereoisomers for ‘A’ is ______.           [2024]



(4)

Major product (A) has two chiral centres and from mechanism of this reaction it is clear that both R and S configurations are possible at both these chiral centres. Hence A has 22=4 stereoisomers.



Q 4 :

When sec-butylcyclohexane reacts with bromine in the presence of sunlight, the major product is :                [2025]

  •  

  •  

  •  

  •  

(4)

In free radical bromination of alkanes, that product is major which is formed by most stable free radical intermediate. Stability of free radicals is 3° > 2° > 1°. Out of two 3° carbons present in sec-butylcyclohexane, carbon I forms more stable free radical as it has more number of α H atoms.

 

 



Q 5 :

The maximum number of RBr producing 2-methylbutane by above sequence of reactions is ______. (Consider the structural isomers only)       [2025]

  • 4

     

  • 1

     

  • 3

     

  • 5

     

(1)

RBrMg+EtherR-Mg-BrH2ORH+Mg(OH)Br

Possible structural isomers of R–Br for RH = 2-methylbutane are obtained by placing Br at any one of the following four places:

 



Q 6 :

Propane molecule on chlorination under photochemical condition gives two di-chloro products, “x” and “y”. Amongst “x” and “y”, “x” is an optically active molecule. How many tri-chloro products (consider only structural isomers) will be obtained from “x” when it is further treated with chlorine under the photochemical condition.        [2025]

  • 3

     

  • 2

     

  • 5

     

  • 4

     

(1)

 



Q 7 :

Which of the following conformations will be the most stable?             [2023]

  •  

  •  

  •  

  •  

(1)

In the 1st option bulky Me groups are at anti position. It has least eclipsing as well as least van der-waal strain.



Q 8 :

All structures given below are of vitamin C. Most stable of them is:                    [2023]

  •  

  •  

  •  

  •  

(1)

 



Q 9 :

The correct sequence of reagents for the preparation of Q and R is:           [2023]

  • (i) Cr2O3,770K,20atm;  (ii) CrO2Cl2,H3O+;  (iii) NaOH;  (iv) H3O+

     

  • (i) Mo2O3,Δ;  (ii) CrO2Cl2,H3O+;  (iii) NaOH;  (iv) H3O+

     

  • (i) CrO2Cl2,H3O+;  (ii) Cr2O3,770K,20atm;  (iii) NaOH;  (iv) H3O+

     

  • (i) KMnO4,OH-;  (ii) Mo2O3,Δ;  (iii) NaOH;  (iv) H3O+

     

(1)

 



Q 10 :

In the following reaction, ‘X’ is                [2023]

  • Cl–CH2(CH2)4CH2–Cl

     

  •  

  •  

  • CH3(CH2)4CH2Cl

     

(3)

This is isomerisation reaction of alkane.

 



Q 11 :

Number of bromo derivatives obtained on treating ethane with excess of Br2 in diffused sunlight is _______.         [2023]



(9)



Q 12 :

Identify A in the following reaction.                         [2026]

  •  

  •  

  •  

  •  

(2)



Q 13 :

Given below are two statements:                              [2026]

Statement I: There are several conformers for n–butane. Out of those conformers,

Statement II: As the dihedral angle increases, torsional strain decreases from (X) to (Y).

In the light of the above statements, choose the correct answer from the options given below:

  • Both Statement I and Statement II are true

     

  • Statement I is false but Statement II is true

     

  • Both Statement I and Statement II are false

     

  • Statement I is true but Statement II is false

     

(1)

Both Statements are correct.



Q 14 :

Ph-CH=CH2HBr(PhCOO)2Product

Consider the above reaction.

A. The reaction proceeds through a more stable radical intermediate.
B. The role of peroxide is to generate H (Hydrogen radical).
C. During this reaction, benzene is formed as a byproduct.
D. 1–Bromo–2–phenylethane is formed as the minor product.
E. The same reaction in absence of peroxide proceeds via carbocation intermediate.

Identify the correct statements. Choose the correct answer from the options given below:    [2026]

  • A, B & D Only

     

  • A, C & E Only

     

  • C, D & E Only

     

  • A & E Only

     

(2)

Ph-CH=CH2HBr(PhCOO)2Ph-CH2-CH2-Br

Anti Markovnikov addition

  • Reaction follows radical addition in presence of peroxide
  • In absence of peroxide follows carbocation mechanism
  • Benzene also formed



Q 15 :

Test Q

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  • Enter Answer here

     

  • Enter Answer here

     

  • Enter Answer here

     

Select one or more options

Enter Answer here