Liquefied Petroleum Gas (LPG) supplied as a domestic and industrial fuel is primarily a mixture of which hydrocarbons?
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APropane and butane
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BMethane and ethane
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CHigh-boiling olefins
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DHigh-boiling naphthenes
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EBenzene and toluene
Answer
Correct Answer: Propane and butane
Explanation
Introduction:LPG is a widely used portable fuel. Understanding its composition explains its storage as a liquid under moderate pressure, its combustion properties, and differences from natural gas and gasoline vapors.
Given Data / Assumptions:
- Application: domestic cooking, space heating, and industrial burners.
- Storage: pressurized cylinders/balls at ambient temperature.
- We seek the principal hydrocarbon constituents.
Concept / Approach:LPG primarily contains C3 and C4 hydrocarbons—propane and butane (including isobutane). These liquefy easily at modest pressures, enabling compact storage and transport. Their volatility and clean-burning character suit household and light industrial uses. Composition may be seasonally adjusted (more propane in colder climates for better vaporization).
Step-by-Step Solution:1) Distinguish LPG from natural gas: natural gas is mostly methane (C1).2) Recall LPG’s storage/pressure behavior consistent with C3–C4 vapors.3) Conclude that propane and butane are the main components.
Verification / Alternative check:Fuel specifications worldwide (e.g., IS/EN/ASTM) define LPG grades by C3/C4 content with limits on impurities, odorant requirements, and vapor pressure ranges.
Why Other Options Are Wrong:Methane/ethane: Describe natural gas/ethane-rich streams, not LPG.High-boiling olefins/naphthenes/aromatics: Not compatible with LPG definition or storage behavior.
Common Pitfalls:Equating LPG with LNG (liquefied natural gas) or CNG; those rely on methane and very different storage conditions (cryogenic or high compression).
Final Answer:Propane and butane