Petroleum and fuels basics: Pick the single WRONG statement from the following set about LPG, flash point, fuel gas from distillation, and naphthalene source.
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ALPG can be used as an automotive fuel and in small furnaces; with oxygen it is also used for metal cutting and heating.
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BThe flash point of a petroleum oil is the minimum temperature at which its vapor ignites momentarily but does not necessarily continue to burn.
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COn crude distillation, roughly tens of normal cubic meters of fuel gas per tonne of feed can be produced (order-of-magnitude statement).
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DMaximum industrial yield of naphthalene is obtained from crude oil distillation.
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ELPG cylinders contain mainly propane and butane hydrocarbons under pressure as liquids.
Answer
Correct Answer: Maximum industrial yield of naphthalene is obtained from crude oil distillation.
Explanation
Introduction:This question checks key fuel terminology and common industrial facts: how LPG is used, what “flash point” means, approximate fuel-gas generation in crude distillation, and the principal source of naphthalene. It asks you to spot the single incorrect statement.
Given Data / Assumptions:
- LPG composition mainly propane/butane with minor propylene/butylene traces.
- Flash point vs. fire point distinction.
- Crude distillation units vent off fuel gas streams of order tens of Nm^3 per tonne.
- Naphthalene is obtained predominantly from coal tar distillation, not crude oil.
Concept / Approach:Evaluate each statement against standard definitions and industry practice. LPG is a versatile fuel and cutting gas (with oxygen). Flash point is a “just ignites briefly” temperature; sustained burning defines the fire point. Crude units produce refinery fuel gas in nontrivial quantities. By contrast, the major commercial source of naphthalene is coal tar from coking operations; crude oil yields are very low.
Step-by-Step Solution:Check (a): True—LPG is widely used in vehicles and for heating; with O2, it supports metal cutting/heating.Check (b): True—flash point implies transient ignition, not sustained burning.Check (c): True as an order-of-magnitude statement for refinery fuel gas production.Check (d): False—maximum naphthalene yield comes from coal tar distillation.Check (e): True—LPG cylinders typically contain propane/butane liquefied under pressure.
Verification / Alternative check:Textbook definitions and refinery process overviews corroborate the flash-point definition and naphthalene's coal-tar origin.
Why Other Options Are Wrong:
- Only (d) is incorrect; (a), (b), (c), and (e) are accurate.
Common Pitfalls:Confusing flash point with fire point, and assuming all aromatics are crude-derived in large quantities.
Final Answer:Maximum industrial yield of naphthalene is obtained from crude oil distillation.