NEET Environmental Chemistry PYQs & Practice Questions

10 free NEET Chemistry questions on Environmental Chemistry, starting with previous year questions (2017–2023). Tap “Show answer” to check each one. No login needed.

Topics: Principles of Green Chemistry · Greenhouse Gases · Photochemical Smog · Classical Smog · Biochemical Oxygen Demand (BOD) · Role of Ozone · Effect of Organic Pollution on Aquatic Life · Photochemical Smog - Oxidising Nature · Atmospheric Layers · Formation of Nitrogen Oxides · Primary and Secondary Air Pollutants · The Ozone Hole

1. Q1NEET 2023Eutrophication

   Given below are two statements: Statement I: The nutrient deficient water bodies lead to eutrophication. Statement II: Eutrophication leads to decrease in the level of oxygen in the water bodies. In the light of the above statements, choose the correct answer from the options given below.

   • A. Both Statement I and Statement II are false.
   • B. Statement I is correct but Statement II is false.
   • C. Statement I is incorrect but Statement II is true.
   • D. Both statement I and Statement II are true.
   Show answer

   Answer: B — Statement I is correct but Statement II is false.

   Statement I is incorrect — it is nutrient-RICH (not nutrient-deficient) water bodies that lead to eutrophication, due to excessive growth of algae and plants from nutrient enrichment. Statement II is correct — eutrophication leads to a decrease in dissolved oxygen levels in water bodies as decomposing organic matter consumes oxygen.

2. Q2NEET 2022Sulphur Oxide Pollution Enhancement

   The pollution due to oxides of sulphur gets enhanced due to the presence of: (a) particulate matter (b) ozone (c) hydrocarbons (d) hydrogen peroxide. Choose the most appropriate answer from the options given below:

   • A. (a), (d) only
   • B. (a), (b), (d) only
   • C. (b), (c), (d) only
   • D. (a), (c), (d) only
   Show answer

   Answer: A — (a), (d) only

   Particulate matter, ozone, and hydrogen peroxide all catalyze or enhance the oxidation of SO2 to SO3/sulphate pollution (acid rain formation), so (a), (b), (d) are correct, while hydrocarbons are not typically listed as enhancing sulphur oxide pollution in this context.

3. Q3NEET 2021Pollution Reactions

   Match List-I with List-II. List-I: (a) 2SO2(g)+O2(g)→2SO3(g) (b) HOCl(g) --hv--> •OH + •Cl (c) CaCO3+H2SO4→CaSO4+H2O+CO2 (d) NO2(g) --hv--> NO(g)+O(g). List-II: (i) Acid rain (ii) Smog (iii) Ozone depletion (iv) Tropospheric pollution. Choose the correct answer from the options given below.

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

   Answer: C — (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)

   (a) SO2 oxidation relates to tropospheric pollution/acid rain precursor (iv). (b) HOCl photolysis relates to ozone depletion (iii). (c) CaCO3+H2SO4 reaction relates to acid rain effect on marble (i). (d) NO2 photolysis relates to smog formation (ii)

4. Q4NEET 2021Matching atmospheric chemical reaction to phenomenon

   Match List-I with List-II: (a) 2SO2(g)+O2(g)→2SO3(g), (b) HOCl(g)--hν-->•OH+•Cl, (c) CaCO3+H2SO4→CaSO4+H2O+CO2, (d) NO2(g)--hν-->NO(g)+O(g) with (i) Acid rain, (ii) Smog, (iii) Ozone depletion, (iv) Tropospheric pollution.

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

   Answer: B — (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)

   SO2+O2→SO3 contributes to acid rain (i); HOCl photolysis releasing •OH/•Cl contributes to ozone depletion (iii); CaCO3 reacting with acid rain (H2SO4) is a tropospheric pollution effect (iv); NO2 photolysis produces smog (ii). (a)-(i),(b)-(iii),(c)-(iv),(d)-(ii).

Practise all 19 Environmental Chemistry questions with a timer

• Timed chapter test
• Score + weak topics
• Full NEET mocks & rank

Start free for 30 days

No payment, no card. Register in 2 minutes.

5. Q5NEET 2020Effects of carbon monoxide on haemoglobin

   Which of the following is not correct about carbon monoxide?

   • A. It forms carboxyhaemoglobin.
   • B. It reduces oxygen carrying ability of blood.
   • C. The carboxyhaemoglobin (haemoglobin bound to CO) is less stable than oxyhaemoglobin.
   • D. It is produced due to incomplete combustion.
   Show answer

   Answer: B — It reduces oxygen carrying ability of blood.

   Carboxyhaemoglobin is actually far more stable (CO binds about 200 times more strongly to haemoglobin) than oxyhaemoglobin, which is why CO poisoning is so dangerous; this statement claiming it is less stable is incorrect.

6. Q6NEET 2019Greenhouse Gases

   Among the following, the one that is not a green house gas is:

   • A. ozone
   • B. sulphur dioxide
   • C. nitrous oxide
   • D. methane
   Show answer

   Answer: A — ozone

   Sulphur dioxide (SO2) is a major air pollutant and contributes to acid rain, but it is not classified as a greenhouse gas. Ozone, nitrous oxide, and methane are all recognized greenhouse gases that trap heat in the atmosphere.

7. Q7NEET 2017Sinks for atmospheric pollutants

   Which of the following is a sink for CO?

   • A. Micro organisms present in the soil
   • B. Oceans
   • C. Plants
   • D. Haemoglobin
   Show answer

   Answer: —

   Microorganisms present in the soil act as a natural sink for carbon monoxide (CO), oxidising it to carbon dioxide and removing it from the atmosphere.

8. Q8Greenhouse Gases

   Which of the following gases is not a greenhouse gas?

   • A. CO
   • B. O3
   • C. CH4
   • D. H2O vapour
   Show answer

   Answer: —

   Carbon monoxide (CO) is a toxic pollutant but is not classified as a greenhouse gas, unlike ozone, methane, and water vapour, which all trap infrared radiation.

Practise all 19 Environmental Chemistry questions with a timer

• Timed chapter test
• Score + weak topics
• Full NEET mocks & rank

Start free for 30 days

No payment, no card. Register in 2 minutes.

9. Q9Photochemical Smog

   Photochemical smog occurs in warm, dry and sunny climate. One of the following is not amongst the components of photochemical smog. Identify it.

   • A. NO2
   • B. O3
   • C. SO2
   • D. Unsaturated hydrocarbon
   Show answer

   Answer: B — O3

   SO2 is characteristic of classical (reducing) smog formed in cold, humid conditions, not photochemical (oxidising) smog, which consists of NO2, O3, PAN, and unsaturated hydrocarbons/aldehydes.

10. Q10Classical Smog

    Which of the following statements is not true about classical smog?

    • A. Its main components are produced by the action of sunlight on automobile or factory emissions.
    • B. It is produced in cold and humid climate.
    • C. It contains compounds of a reducing nature.
    • D. It contains smoke, fog and sulphur dioxide.
    Show answer

    Answer: —

    Classical (London-type) smog forms from the reaction of smoke, fog, and SO2 in cold, humid weather, and does not require sunlight. The description of sunlight acting on emissions actually applies to photochemical smog, not classical smog.