Question

The correct relation of the Octane number for the following is:

• A. straight chain $>$ branched chain
• B. straight chain $<$ branched chain
• C. straight chain $=$ branched chain
• D. both A and B

Answer 1

The correct option is B straight chain $<$ branched chain

The octane number of a fuel is based on how fuels auto-ignite, under compression.

1. It is based on the scale where isooctane is 100 (minimal ignition under pressure) and heptane is 0 (easily ignites under pressure).

2. Octane rating decreases with an increase in the carbon chain length.

3. Octane ratings increase with carbon chain branching.

4. Octane ratings increase in aromatics with the same number of carbons.

Hence, the correct option is $B$.