Octane number reference compound: Iso-octane is used as the 100-point reference for octane number. Its correct chemical name is:
Chemical Engineering
Petroleum Refinery Engineering
Difficulty: Easy
Choose an option
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Aα-methyl naphthalene
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B2,2,4-trimethylpentane
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C1,3-butadiene
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DTetramethylethylene
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E3-ethylhexane
Answer
Correct Answer: 2,2,4-trimethylpentane
Explanation
Introduction:Octane number compares gasoline knock resistance to a reference blend of iso-octane (defined as 100) and n-heptane (defined as 0). The question asks for the correct chemical name of iso-octane.
Given Data / Assumptions:
- Standard octane definition is implied.
Concept / Approach:Iso-octane is the branched paraffin 2,2,4-trimethylpentane. Its high knock resistance under spark-ignition conditions makes it the 100 reference point.
Step-by-Step Solution:
Recall the definition of octane number.Match “iso-octane” to its IUPAC name: 2,2,4-trimethylpentane.Eliminate other compounds which are unrelated or unsaturated/aromatic.Verification / Alternative check:Fuel property tables list iso-octane explicitly as 2,2,4-trimethylpentane.
Why Other Options Are Wrong:
- α-methyl naphthalene: Aromatic; historical cetane reference, not octane.
- 1,3-butadiene / Tetramethylethylene: Olefins, not the octane standard.
- 3-ethylhexane: Another isomer, not the octane reference.
Common Pitfalls:Mixing up octane and cetane reference compounds.
Final Answer:2,2,4-trimethylpentane