The GATE Grind

GATE 2023 CH – Question 15

Chemical Technology · Petroleum refining and petrochemicals · 1 mark · Multiple choice

Which one of the following statements related to octane number is NOT correct?

  1. Linear alkanes with higher carbon number have higher octane number.
  2. Branching in linear alkanes increases their octane number.
  3. Catalytic reforming of hydrocarbons increases their octane number.
  4. Gasoline quality is measured in terms of octane number.

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Correct answer: (A) Linear alkanes with higher carbon number have higher octane number.

Explanation

For straight-chain alkanes the octane number falls as the chain gets longer (n-heptane is 0 and n-hexane is 25). Branching, as in iso-octane (100), and reforming increase it, and the octane number is the standard quality measure of gasoline.