NEET 2025: Organic Chemistry PYQ – Basic Principles and Techniques

Q 1 :
Match List I with List II. [2024]

List I List II

(Molecule) (Number and types of bond/s between two carbon atoms)

A. Ethane I. one $σ$ -bond and two $π$ -bonds

B. Ethene II. two $π$ -bonds

C. Carbon molecule, $C_{2}$ III. one $σ$ -bond

D. Ethyne IV. one $σ$ -bond and one $π$ -bond

Choose the correct answer from the options given below:

A-I, B-IV, C-II, D-III
A-IV, B-III, C-II, D-I
A-III, B-IV, C-II, D-I
A-III, B-IV, C-I, D-II

1

2

3

4

(3)

[IMAGE 44]

One $σ$ -bond between C atoms (A - III).

[IMAGE 45]

One $σ$ -bond and 1 $π$ -bond between C atoms (B - IV).

$C_{2}$ molecule: Two $π$ -bonds (C - II)

Ethyne: $H — C \equiv C — H$

One $σ$ -bond and two $π$ -bonds (D - I)

Q 2 :
The number of sigma ( $σ$ ) and pi ( $π$ ) bonds in pent-2-en-4-yne is [2019]

13 σ bonds and no $π$ bond
10 σ bonds and 3 $π$ bonds
8 σ bonds and 5 $π$ bonds
11 σ bonds and 2 $π$ bonds.

1

2

3

4

(2)

[IMAGE 46]

Correct name will be pent-3-en-1-yne

Q 3 :
Which of the following molecules represents the order of hybridisation $s p^{2}$ , $s p^{2}$ , $sp$ , $sp$ from left to right atoms? [2018]

$HC \equiv C - C \equiv CH$
${CH}_{2} = CH - C \equiv CH$
${CH}_{2} = CH - CH = {CH}_{2}$
${CH}_{3} - CH = CH - {CH}_{3}$

1

2

3

4

(2)

$\overset{{sp}^{2}}{{CH}_{2}} = \overset{{sp}^{2}}{CH} - \overset{sp}{C} \equiv \overset{sp}{CH}$

Q 4 :
The total number of $π$ -bond electrons in the following structure is [2015]

[IMAGE 47]

12
16
4
8

1

2

3

4

(4)

There are four double bonds. Hence, no. of $π$ -electrons = 2 × 4 = 8.

Topic Question Set

Q 2 :
The number of sigma ( $σ$ ) and pi ( $π$ ) bonds in pent-2-en-4-yne is [2019]

Q 3 :
Which of the following molecules represents the order of hybridisation $s p^{2}$ , $s p^{2}$ , $sp$ , $sp$ from left to right atoms? [2018]

Q 4 :
The total number of $π$ -bond electrons in the following structure is [2015]

[IMAGE 47]

Want Us to Email you About Special Offers & Updates?

	List I		List II
	(Molecule)		(Number and types of bond/s between two carbon atoms)
A.	Ethane	I.	one $σ$ -bond and two $π$ -bonds
B.	Ethene	II.	two $π$ -bonds
C.	Carbon molecule, $C_{2}$	III.	one $σ$ -bond
D.	Ethyne	IV.	one $σ$ -bond and one $π$ -bond

Topic Question Set

Q 2 : The number of sigma (σ) and pi (π) bonds in pent-2-en-4-yne is [2019]

Q 3 : Which of the following molecules represents the order of hybridisation sp2, sp2, sp, sp from left to right atoms? [2018]

Q 4 : The total number of π-bond electrons in the following structure is [2015] [IMAGE 47]

Want Us to Email you About Special Offers & Updates?

Q 2 :
The number of sigma ( $σ$ ) and pi ( $π$ ) bonds in pent-2-en-4-yne is [2019]

Q 3 :
Which of the following molecules represents the order of hybridisation $s p^{2}$ , $s p^{2}$ , $sp$ , $sp$ from left to right atoms? [2018]

Q 4 :
The total number of $π$ -bond electrons in the following structure is [2015]

[IMAGE 47]