Chapter 7, Problem 1P

Interpretation Introduction

Interpretation:

Whether a gasoline can have octane number more than 100 is to be explained.

Concept Introduction:

A number which is used to measure the antiknock properties of a fuel like gasoline is known as octane number.

A standard measure of the performance of a liquid fuel or engine is known as octane number. The high value of octane number results in the more compression of the fuel which can withstand before igniting, whereas, the low value of octane number is ideal for diesel engines.

Answer to Problem 1P

Yes, it is possible for a gasoline with octane number more than 100.

Explanation of Solution

Whether the combustion of gasoline can occur smoothly is identified quantitatively by octane number of the gasoline. This is defined by selecting one compound as a reference which causes high amount of knocking and another which causes negligible or no knocking.

In early days, pure 2,2,4-trimethylpentane burns smoothly (no knocking) is identified and octane number was assigned as 100 whereas pure heptane caused knocking while combustion and octane number was assigned as 0.

A standard mixture of these compounds defines a scale from 0 to 100 for determining the knocking is caused by gasolines which are real. If a sample of gasoline results in similar quantity of knocking in a test engine as a mixture of 10 % of heptane and 2,2,4-trimethylpentane and it is allotted the octane number as 90.

But if a gasoline (particular) sample results in less amount of knocking in a test engine in comparison to knocking resulted by a mixture of 100 % 2,2,4-trimethylpentane and 0 % heptane, then octane number is assigned as more than 100.

Hence, it is possible for a gasoline having octane number more than 100.