Question

A fuel has octane no. of $60$. This indicates that fuel has the knocking tendency equal to:

• A. $60$% n-heptane + $40$% iso octane
• B. $60$% n-octane + $40$% isoheptane
• C. $60$% isooctane + $40$% n-heptane
• D. $60$% isoheptane + $40$% n-octane

Answer 1

The correct option is C $60$% isooctane + $40$% n-heptane

The octane rating of gasoline is measured in a test engine and is defined by comparison with the mixture of $2,2,4$-trimethylpentane (iso-octane) and heptane that would have the same anti-knocking capacity as the fuel under test: the percentage, by volume, of $2,2,4$-trimethylpentane in that mixture is the octane number of the fuel.