Industrial safety — properties of sulphur dioxide (SO₂) Evaluate the statement: “Sulphur dioxide is extremely toxic and non-flammable.” Choose the correct option.

Introduction / Context:
Sulphur dioxide (SO₂) is encountered in flue gases, acid manufacturing, and some refrigeration histories. Knowing its hazard profile is essential for ventilation, leak response, and personal protective equipment selection.

Given Data / Assumptions:

• SO₂ at typical industrial temperatures and pressures.
• Focus on toxicity and flammability only.

Concept / Approach:
SO₂ is a corrosive, highly irritating gas with a pungent odor. It is toxic by inhalation and contact with moist tissues (forming sulphurous acid). However, it does not support combustion and is generally classified as non-flammable. Thus the combined statement is correct.

Step-by-Step Solution:
Assess toxicity: SO₂ causes respiratory distress even at low ppm; at higher concentrations it is dangerous.Assess flammability: SO₂ lacks a flammable range in air under normal conditions and does not sustain flames.Conclude the statement “extremely toxic and non-flammable” holds.

Verification / Alternative check:
Safety data sheets (SDS) list SO₂ hazard statements for acute toxicity and corrosion but do not assign flammability ratings typical of hydrocarbons.

Why Other Options Are Wrong:
(b) contradicts the known properties. (c), (d), (e) add conditions that do not change the toxicity/flammability assessment in normal practice.

Common Pitfalls:
Confusing SO₂ with SO₃ or with combustible sulphur vapors; only elemental sulphur dust can pose combustion risks, not SO₂ gas.

Final Answer:
True