Q.54 Chemistry ⭐ 360° Option Elimination Active

NEET 2026 Chemistry Question 54 Solution

Topic: Solutions · Official NTA Booklet Code 50

Question

Assertion A: For an ideal solution formed by mixing liquids P and Q, ΔmixH = 0 and ΔmixV = 0. Reason R: No interactions occur between P and Q. In the light of the above statements, choose the most appropriate answer from the options given below.

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Verified Against NTA Final Answer Key

Option (3) : A is correct but R is not correct

📚 Solutions Easy

📋 Given Parameters & Problem Setup

Assertion (A) For an ideal solution formed by mixing liquids P and Q, Δ_mix H = 0 and Δ_mix V = 0

Reason (R) No interactions occur between P and Q

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The 30-Second Exam Hall Shortcut: ⚡ The "No Interaction" Fallacy Detector

⏱️ Save ~40 seconds

Liquids MUST have intermolecular interactions! In ideal solutions, interactions are EQUAL, not absent!

1 Check Assertion A: By definition, an ideal solution has Δ_mix H = 0 and Δ_mix V = 0 -> TRUE.

2 Check Reason R: "No interactions occur between P and Q" -> FALSE! If there were no interactions, it would be an ideal gas, not a condensed liquid solution.

3 True scientific reason: The P-Q intermolecular interactions are identical in magnitude to P-P and Q-Q interactions.

4 Conclusion: Assertion is correct, Reason is incorrect -> Option (3) immediately!

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Why You Can 100% Trust This Shortcut: NCERT Solutions textbook core definition: In ideal solutions, the intermolecular attractive forces between A-A and B-B are nearly equal to those between A-B.

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Evaluate Assertion A: Thermodynamic Criteria of Ideal Solutions

An ideal solution is defined as one that obeys Raoult’s law over the entire range of concentration. For such solutions: 1. Enthalpy of mixing is zero (Δ_mix H = 0), meaning no heat is absorbed or evolved. 2. Volume of mixing is zero (Δ_mix V = 0), meaning the total volume equals the sum of the individual volumes.

\Delta_{\text{mix}}H = 0 \quad \text{and} \quad \Delta_{\text{mix}}V = 0

• Assertion A is scientifically correct.

Step 2

Evaluate Reason R: Nature of Intermolecular Forces

In liquid solutions, intermolecular cohesive forces (such as dipole-dipole, London dispersion, or van der Waals forces) are always present. An ideal solution does not mean "zero interaction". Rather, it means that the magnitude of solute-solvent (P-Q) intermolecular interactions is EQUAL to solute-solute (P-P) and solvent-solvent (Q-Q) interactions.

F_{\text{P-Q}} \approx F_{\text{P-P}} \approx F_{\text{Q-Q}} \neq 0

• Because the bond-breaking energy of P-P and Q-Q equals the bond-making energy of P-Q, Δ_mix H = 0.
• Reason R claims "No interactions occur", which is scientifically false.

Step 3

Formulate the Final Answer

Since Assertion A is a correct factual statement and Reason R is scientifically false, the correct choice is: A is correct but R is not correct.

\text{Assertion A: TRUE}, \quad \text{Reason R: FALSE} \implies \text{Option (3)}

• Matches Option (3).

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan

1 A

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Reason R is false because liquids always possess intermolecular interactions.

⚠️

Student Fallacy (Why candidates pick this trap): Equating ideal solutions with ideal gases where intermolecular forces are assumed zero.

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. R is false, not correct.

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Student Fallacy (Why candidates pick this trap): Failing to spot the false claim in Reason R.

3 C

✓ 100% Correct

Verdict & Scientific Reason:

Scientifically rigorous. A correctly describes ideal thermodynamics, while R makes a fundamentally incorrect physical claim.

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Why this is airtight: None; recognizes the distinction between identical interactions and zero interactions.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Assertion A is a textbook definition of an ideal solution.

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Student Fallacy (Why candidates pick this trap): Doubting the thermodynamic definition of ideal mixtures.

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NTA Trap Alert: Confusing Ideal Solution with Ideal Gas

Students frequently confuse kinetic molecular theory of ideal gases (where gas particles exert no attractive forces) with liquid solutions. In liquid solutions, forces are essential to hold the liquid state together!

🛡️ How to avoid the -1 mark: Liquid solutions MUST have forces. Ideal solution means P-Q forces EQUAL P-P and Q-Q forces.

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Core NEET Syllabus Standard

NEET Chemistry Core Syllabus · Solutions Standard Benchmark

Core Scientific Principle Tested:

"Ideal solutions form when intermolecular attractive forces between components are equal in magnitude."

Syllabus Focus: Ideal and non-ideal solutions, Raoult's law

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Ideal liquids have MATCHING forces, not MISSING forces!

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NEET 2026 Chemistry Question 54 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ The "No Interaction" Fallacy Detector

Step-by-Step Rigorous Workflow & Mathematical Proof

Evaluate Assertion A: Thermodynamic Criteria of Ideal Solutions

Evaluate Reason R: Nature of Intermolecular Forces

Formulate the Final Answer

360° Option Elimination Engine Key Feature

NTA Trap Alert: Confusing Ideal Solution with Ideal Gas

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Solutions

Classification of Solutions: Solute and Solvent States

Highest Boiling Point of Aqueous Solutions (Effective Molality / Osmolarity)

Identification of Deviation from Raoult’s Law from Vapor Pressure Measurements

Henry’s Law Constant and Gas Solubility in Liquids

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