Top Surface Chemistry Questions for NEET
Surface chemistry is one of the most scoring and concept-driven chapters for NEET aspirants. Every year, direct and application-based questions appear from adsorption, colloids, emulsions, and catalysis. Mastering the Top 5 Surface Chemistry Questions ensures that you build a strong conceptual base while also preparing for repeated PYQs. In this article, we cover the Top 5 Surface Chemistry Questions with detailed explanations, followed by additional practice questions for rapid revision.
Why Surface Chemistry is Important for NEET
Surface chemistry carries consistent weightage in NEET. Questions are often NCERT-based and revolve around adsorption isotherms, colloidal properties, and catalysis. Practicing the Top 5 Surface Chemistry Questions not only helps in scoring but also strengthens conceptual clarity, especially in numericals and assertion-reason type questions.
Top 5 Surface Chemistry Questions (NCERT-Based PYQs)
Question 1: Freundlich Adsorption Isotherm
The Freundlich adsorption isotherm is given by:mx=kP1/n
Which of the following statements is correct?
A. Valid only at high pressure
B. Valid only at low pressure
C. Empirical relation valid over a limited range
D. Independent of temperature
Answer: C
Explanation:
The Freundlich isotherm is an empirical relation that holds good over a limited pressure range. It does not work at very high pressures because adsorption reaches saturation. Among the Top 5 Surface Chemistry Questions, this is frequently asked because it directly comes from NCERT.
Question 2: Physical vs Chemical Adsorption
Which of the following is true for physisorption?
A. High activation energy
B. Irreversible
C. Involves van der Waals forces
D. Forms multilayer adsorption
Answer: C and D
Explanation:
Physisorption involves weak van der Waals forces and can form multilayers. It has low activation energy and is reversible. These concepts are crucial when solving Top 5 Surface Chemistry Questions in NEET.
Question 3: Colloidal Solution Stability
Which factor is responsible for the stability of a colloidal solution?
A. Brownian motion
B. Charge on particles
C. Tyndall effect
D. Density difference
Answer: B
Explanation:
The stability of colloids arises due to the presence of like charges on particles, preventing aggregation. Brownian motion helps dispersion but does not ensure stability. This concept is often tested in Top 5 Surface Chemistry Questions.
Question 4: Hardy-Schulze Rule
According to Hardy-Schulze rule, which ion is most effective in coagulating a negatively charged sol?
A. Na⁺
B. Ca²⁺
C. Al³⁺
D. Cl⁻
Answer: C
Explanation:
The coagulating power increases with the valency of the ion opposite in charge to the sol. Since the sol is negatively charged, the cation with highest charge (Al³⁺) is most effective. This is one of the most repeated Top 5 Surface Chemistry Questions.
Question 5: Catalyst Function
Which statement is correct regarding catalysts?
A. Change equilibrium constant
B. Increase activation energy
C. Provide alternative reaction pathway
D. Get consumed permanently
Answer: C
Explanation:
Catalysts lower activation energy by providing an alternative pathway without affecting equilibrium. This is a conceptual highlight in Top 5 Surface Chemistry Questions.
Key Concepts You Must Remember
While solving the Top 5 Surface Chemistry Questions, keep these concepts crystal clear. Adsorption depends on surface area, pressure, and temperature. Physisorption decreases with increasing temperature, while chemisorption increases initially. Colloids show properties like Tyndall effect and Brownian motion. Emulsions require emulsifiers for stability. Catalysts speed up reactions without changing equilibrium.
Additional Practice Questions (Concept-Based Rapid Revision)
Question 6
Which adsorption is accompanied by decrease in entropy?
Answer: Adsorption in general decreases entropy because molecules become more ordered on the surface.
Question 7
Which type of catalyst increases the rate of reaction?
Answer: Positive catalyst
Question 8
Which property is used to distinguish colloids from true solutions?
Answer: Tyndall effect
Question 9
Which colloid has liquid dispersed in liquid?
Answer: Emulsion
Question 10
Which method is used to purify colloids?
Answer: Dialysis
Additional Practice Questions with Solutions
Question 11
Why does physisorption decrease with temperature?
Solution:
Physisorption is exothermic. Increasing temperature supplies energy to adsorbed molecules, causing desorption.
Question 12
Why are catalysts not consumed in reactions?
Solution:
Catalysts participate in intermediate steps but regenerate at the end, so they are not consumed overall.
Question 13
Why is lyophilic colloid stable?
Solution:
Strong interaction between dispersed phase and dispersion medium stabilizes it.
Question 14
What is the role of emulsifier?
Solution:
It stabilizes emulsions by forming a protective layer between immiscible liquids.
Question 15
Why is Al³⁺ more effective than Na⁺ in coagulation?
Solution:
Higher charge leads to greater neutralization of colloidal particles, increasing coagulation efficiency.
Final Revision Tips
To master the Top 5 Surface Chemistry Questions, focus on NCERT definitions, examples, and graphs. Revise adsorption isotherms, types of catalysis, and colloidal properties regularly. Practice assertion-reason questions since NEET frequently tests conceptual understanding rather than direct theory.
Consistent revision of the Top 5 Surface Chemistry Questions will ensure you can solve both straightforward and tricky problems confidently in the exam.