Question

Is it possible for motor fuel to have a negative octane rating? Explain.

Short answer

If a fuel has a negative octane rating then such fuel causes more "knocking" than$\mathrm{n}$ -heptane which is worst at the time.

Step-by-step solution

High performance.

The octane rating on gas pumps indicates how resistant a motor fuel is to knocking that is, making pinging or ticking sounds in a car's engine when you stomp on the gas pedal. The octane number is also known as the octane rating. Isooctane is$100$ and heptane is $0.$The greater the octane rating, the more compression is needed to ignite the fuel.

Spark ignition engine.

In diesel engines, where the gasoline is not compressed, low octane (or high cetane) fuels are employed. Using fuel with a low octane rating in a spark-ignition engine can create pre-ignition and engine knock, which can cause engine damage. Compressing the air-fuel mixture may cause the fuel to detonate before the spark plug's flame front reaches it.A fuel's octane rating might be negative.

Such a figure would imply that the gasoline produces greater "knocking" than $\mathrm{n}$-heptane, which was considered "the worst" at the time.