Environmental Chemistry NDA Questions

NDA Chemistry

Environmental Chemistry MCQ Questions


13.
SULPHUR DIOXIDE (SO₂) is a major air pollutant. Its most important harmful effect is:
A.
SO₂ is responsible for formation of photochemical smog through NOₓ reactions
B.
SO₂ is a greenhouse gas that causes global warming like CO₂
C.
It causes ACID RAIN when oxidised to SO₃ and dissolved in water (SO₃ + H₂O → H₂SO₄), and directly damages respiratory tract, irritates eyes and causes bronchitis
D.
SO₂ depletes the stratospheric ozone layer by releasing sulphur radicals
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ANSWER :
C. It causes ACID RAIN when oxidised to SO₃ and dissolved in water (SO₃ + H₂O → H₂SO₄), and directly damages respiratory tract, irritates eyes and causes bronchitis
14.
PARTICULATE POLLUTANTS in the troposphere include various types. The most HARMFUL to human health are:
A.
Coarse particles (PM₁₀ — particles 2.5 to 10 µm) that are trapped in the nose
B.
Asbestos fibres which are too large to enter the respiratory system
C.
Very fine particles (PM₂.₅ — particles less than 2.5 µm diameter) that penetrate deepest into lungs, reaching alveoli and entering the bloodstream
D.
Lead and mercury vapours which are gaseous, not particulate pollutants
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ANSWER :
C. Very fine particles (PM₂.₅ — particles less than 2.5 µm diameter) that penetrate deepest into lungs, reaching alveoli and entering the bloodstream
15.
ACID RAIN is caused by the presence of which acids in rainwater?
A.
Carbonic acid only from dissolution of CO₂ in rainwater (normal slightly acidic rain)
B.
Sulphuric acid (H₂SO₄) — from oxidation of SO₂, and Nitric acid (HNO₃) — from oxidation of NOₓ dissolved in rainwater
C.
Hydrochloric acid and hydrobromic acid from burning of chlorinated compounds
D.
Phosphoric acid from burning of phosphorus compounds in industry
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ANSWER :
B. Sulphuric acid (H₂SO₄) — from oxidation of SO₂, and Nitric acid (HNO₃) — from oxidation of NOₓ dissolved in rainwater
16.
ACID RAIN causes damage to the TAJ MAHAL. What is the chemical reaction responsible?
A.
The acidic pH dehydrates the marble causing it to crack mechanically
B.
Acid rain reacts with the decorative semi-precious stones to form coloured compounds
C.
CaCO₃ (marble/limestone) + H₂SO₄ → CaSO₄ + H₂O + CO₂ — the acid converts calcium carbonate to calcium sulphate, which then crumbles and washes away
D.
Acid rain causes direct corrosion of the marble surface by stripping electrons
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ANSWER :
C. CaCO₃ (marble/limestone) + H₂SO₄ → CaSO₄ + H₂O + CO₂ — the acid converts calcium carbonate to calcium sulphate, which then crumbles and washes away
17.
The pH of normal rainwater is approximately:
A.
8.5 (slightly alkaline — due to dissolved minerals)
B.
4.0 (strongly acidic — acid rain level)
C.
7.0 (neutral — pure water)
D.
5.6 — slightly acidic due to dissolved carbon dioxide forming carbonic acid: CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻
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ANSWER :
D. 5.6 — slightly acidic due to dissolved carbon dioxide forming carbonic acid: CO₂ + H₂O ⇌ H₂CO₃ ⇌ H⁺ + HCO₃⁻
18.
What are the harmful effects of ACID RAIN?
A.
Only causes breathing problems in humans — no effect on materials or ecosystems
B.
Damages monuments (marble cancer), acidifies soil (reduced crop yield), acidifies lakes (kills aquatic life), corrodes metals, damages forests (especially conifers) and irritates eyes/skin
C.
Only bleaches coloured fabrics — no effect on living organisms
D.
Causes global warming by increasing atmospheric temperature
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ANSWER :
B. Damages monuments (marble cancer), acidifies soil (reduced crop yield), acidifies lakes (kills aquatic life), corrodes metals, damages forests (especially conifers) and irritates eyes/skin