Organic Chemistry Some Basic Principles and Techniques JEE Main PYQs (2020–2026)

Solved Organic Chemistry Some Basic Principles and Techniques PYQs

3 recent questions with answers. The full set of 216 is free to practise.

1. JEE Main 2026EasyPurification and Elemental Analysis of Organic Compounds
   Q1

   Given below are two statements :
   
   Statement I : Vapours of the liquid with higher boiling point condense before vapours of the liquid with lower boiling points in fractional distillation.
   
   Statement II : The vapours rising up in the fractionating column become richer in high boiling component of the mixture.
   
   In the light of the above statements, choose the correct answer from the options given below :

   • ABoth Statement I and Statement II are true
   • BBoth Statement I and Statement II are false
   • CStatement I is true but Statement II is false
   • DStatement I is false but Statement II is true

   Show answer & solution

   Correct answer: (C)

   Let us analyse both statements carefully using the concept of fractional distillation as given in NCERT.
   
   Concept:
   
   Fractional distillation is a process used to separate a mixture of two or more liquids having different boiling points.
   
   The liquid having a lower boiling point vaporises first.
   
   As vapours rise through the fractionating column, they repeatedly condense and vaporise.
   
   The temperature in the column gradually decreases from bottom to top.
   
   Hence, vapours rising upwards become richer in the more volatile (lower boiling point) component.
   
   Statement I
   
   “Vapours of the liquid with higher boiling point condense before vapours of the liquid with lower boiling points in fractional distillation.”
   
   Liquids with higher boiling point are less volatile.
   
   Thus, their vapours condense earlier (lower in the column) because they require a lower temperature difference to liquefy.
   
   Therefore, Statement I is true.
   
   Statement II
   
   “The vapours rising up in the fractionating column become richer in high boiling component of the mixture.”
   
   As explained, the rising vapours become richer in the low boiling or more volatile component, not the high boiling one.
   
   Therefore, Statement II is false.
   
   Correct Answer:
   
   Option C: Statement I is true but Statement II is false
2. JEE Main 2026EasyReactive Intermediates and Reaction Mechanisms
   Q2

   Identify the correct statements :
   
   The presence of –NO2 group in benzene ring
   
   A. activates the ring towards electrophilic substitutions.
   
   B. deactivates the ring towards electrophilic substitutions.
   
   C. activates the ring towards nucleophilic substitutions.
   
   D. deactivates the ring towards nucleophilic substitutions.
   
   Choose the correct answer from the options given below :

   • AA and D Only
   • BB and D Only
   • CC and A Only
   • DB and C Only

   Show answer & solution

   Correct answer: (D)

   Presence of ${NO}_2$ group on the benzene ring deactivates the ring towards electrophilic substitution reactions because it shows $-M$ effect (it withdraws electrons from the ring by resonance).
   
   Because the ${NO}_2$ group pulls electron density away, the ring becomes less reactive towards electrophiles.
   
   At the same time, the ${NO}_2$ group activates the ring towards nucleophilic substitution because the withdrawal of electrons makes the ring more suitable for attack by nucleophiles (electron-rich species).
   
   Ans. $\to$ B & C
3. JEE Main 2026MediumElectronic Displacement Effects and Aromaticity
   Q3

   Find out the statements which are not true.
   
   A. Resonating structures with more number of covalent bonds and lesser charge separation are more stable.
   
   B. In electromeric effect, an unsaturated system shows +E effect with nucleophile and -E effect with electrophile.
   
   C. Inductive effect is responsible for high melting point, boiling point and dipole moment of polar compounds.
   
   D. The greater the number of alkyl groups attached to the doubly bonded carbon atoms, higher is the heat of hydrogenation.
   
   E. Stability of carbanion increases with the increase in $s-$ character of the carbon carrying the negative charge.
   
   Choose the correct answer from the options given below :

   • AA, D & E only
   • BA, C & D only
   • CB & D only
   • DB, D & E only

   Show answer & solution

   Correct answer: (C)

   $$\text{ Statement B \& D are not true }$$

Topic-wise question count

Where JEE Main has asked from Organic Chemistry Some Basic Principles and Techniques, most frequent first.

• Electronic Displacement Effects and Aromaticity40
• Reactive Intermediates and Reaction Mechanisms38
• Purification and Elemental Analysis of Organic Compounds36
• Nomenclature, Classification and Physical Properties of Organic Compounds35
• Stereoisomerism: Geometrical and Optical Isomerism28
• Acidic and Basic Strengths of Organic Compounds22
• Structural Isomerism and Conformations17

Year-wise Organic Chemistry Some Basic Principles and Techniques questions in JEE Main

Number of questions from this chapter in each year's paper(s).