UGC NET Environmental Science Unit 2 PYQs, Important Questions

UGC NET Environmental Science Unit 2 focuses on Environmental Chemistry and covers important topics such as water chemistry, atmospheric chemistry, environmental pollutants, chromatography, thermodynamics, reaction kinetics, wastewater treatment, and analytical techniques. Questions from this unit are frequently asked in the examination and often test both conceptual understanding and numerical application.

The UGC NET Environmental Science examination is scheduled for June 30, 2026, and will be conducted by the National Testing Agency (NTA) in the First Shift from 09:00 AM to 12:00 PM. As the exam approaches, practicing Previous Year Questions (PYQs) can help candidates understand the exam pattern, identify important topics, and strengthen their preparation.

Students who want detailed solutions and explanations of the PYQs can watch the attached video lecture for better understanding and revision.

UGC NET Environmental Science Unit 2 PYQs

Environmental Chemistry is an important part of the UGC NET Environmental Science Unit 2. The following previous-year questions cover topics such as water treatment, greenhouse gases, chromatography, gasification, water chemistry, and environmental pollutants. 

Practicing these questions can help candidates understand important concepts and frequently asked themes in the examination.

Q1. The rate of formation of disinfection byproducts (DBPs) during water treatment is dependent on:

A. Presence of organic precursors
B. Free chlorine concentration
C. Bromide concentration
D. pH
E. Temperature

Choose the correct answer from the options given below:

(A) B and C only
(B) A, D, and E only
(C) A, B, D, and E only
(D) A, B, C, D, E

Q2. Match the List-I and List-II.

Choose the correct answer from the options given below:

(A) (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv)
(B) (a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)
(C) (a)-(ii), (b)-(iii), (c)-(i), (d)-(iv)
(D) (a)-(iii), (b)-(i), (c)-(ii), (d)-(iv)

Q3. A 25 mL sample of treated wastewater requires 175 mL of distilled water to reduce the odor to a level that is just detectable. What is the Threshold Odor Number (TON)?

(A) 7.0
(B) 8.0
(C) 150.0
(D) 200.0

Q4. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion (A): Dioxins and furans are chlorinated compounds that have somewhat similar chemical structures.

Reason (R): They both consist of two benzene rings that are linked together with oxygen bridges.

In the light of the above statements, choose the most appropriate answer from the options given below.

(A) Both A and R are correct and R is the correct explanation of A
(B) Both A and R are correct but R is NOT the correct explanation of A
(C) A is correct but R is not correct
(D) A is not correct but R is correct

Q5. Identify the Boudouard reaction from various gas-solid reactions during biomass gasification process.

(A) C + ½ O₂ ↔ CO
(B) C + CO₂ ↔ 2CO
(C) C + H₂O ↔ H₂ + CO
(D) C + 2H₂ ↔ CH₄

Q6. Which of the following detectors are best suited for HPLC?

A. Mass spectrometer (MS)
B. Thermal Conductivity
C. Absorbance
D. Flame ionization

Choose the correct answer from the options given below:

(A) A only
(B) B and C only
(C) A and C only
(D) A, B, C, and D

Q7. Given below are two statements: one is labelled as Assertion A, and the other is labelled as Reason R.

Assertion (A): DDT caused large-scale mortality among fish-eating birds.

Reason (R): DDT tends to undergo bioaccumulation and biomagnification.

In light of the above statements, choose the most appropriate answer from the options given below.

(A) Both A and R are correct, and R is the correct explanation of A
(B) Both A and R are correct, but R is NOT the correct explanation of A
(C) A is correct, but R is not correct
(D) A is not correct, but R is correct

Q8. Match the List-I and List-II.

Choose the correct answer from the options given below:

(A) (a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)
(B) (a)-(iv), (b)-(ii), (c)-(iii), (d)-(i)
(C) (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)
(D) (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)

Q9. Consider the following statements about the solubility of gases in surface water.

A. Equilibrium concentration of a dissolved gas in water, as per Henry’s law, is referred to as its saturation value.
B. There may be more dissolved gas in water than its saturation value in water.
C. It is more common for a dissolved gas to be present in less amount in water than its saturation value in water.
D. The excess or deficit of a dissolved gas compared to its saturation value cannot be brought back to the saturation level in water.
E. Solubility of gas depends on the partial pressure of the gas but is independent of the purity of water.

Choose the correct answer from the options given below:

(A) A, B, C, and E Only
(B) A, B, and C Only
(C) A, B, C, and D Only
(D) A, C, D, and E Only

Q10. Which of the following processes in the gasification of waste is endothermic?

(A) C + O₂ → CO₂
(B) C + H₂O → CO + H₂
(C) C + 2H₂ → CH₄
(D) 2C + O₂ → 2CO

UGC NET Environmental Science Unit 2 is a highly scoring unit because many questions are concept-based, and several topics are repeated in different examination cycles. Candidates should focus on chromatography, thermodynamics, water chemistry, environmental pollutants, analytical instruments, and reaction kinetics. Regular practice of PYQs helps improve conceptual understanding and builds confidence for the examination.