Question

Calculate the octane number of gasoline fuel, which contains $\text{25\%}\text{n-heptane}$ and $75\%$ is $\text{iso-octane}$ .

• A. 25
• B. 50
• C. 75
• D. 100

Answer 1

Answer: (C)

Octane number is defined as the percentage by volume of iso-octane present in the mixture of $iso-octane$ and $n-heptane$ which has the same antiknocking properties as the fuel under examination.

Given fuel (25% n-heptane +75% iso-octane) Hence, octane number = 75 (because iso octane is 75%)