Problem 32 - A Complete Resource Book in Chemistry for JEE Main

Question

Octane number of gasoline can be increased by the addition of BTX. BTX stands for (a) Butane, TEL, xylene (b) Butane, tetramethyl lead, xylene (c) Benzene, toluene, xylene (d) Benzene, TEL, xylene

Step-by-Step Solution

Answer

The correct answer is (c) Benzene, toluene, xylene.

Step 1: Identify the acronym components

BTX is an acronym used in chemistry, and we need to identify what these letters stand for. The letters B, T, and X correspond to specific compounds' names.

Step 2: Analyze Options

Examine each option and determine what B, T, and X stand for in the context of BTX: - (a): Butane, TEL, xylene - (b): Butane, tetramethyl lead, xylene - (c): Benzene, toluene, xylene - (d): Benzene, TEL, xylene

Step 3: Define BTX

BTX stands for Benzene, Toluene, and Xylene. This combination refers to aromatic hydrocarbons that are often used as additives to enhance fuel properties.

Step 4: Choose the correct answer

Compare the definition of BTX from Step 3 with the options provided: - Step 3's definition matches option (c). Benzene, toluene, xylene as these are the classical aromatic compounds known collectively as BTX.

Key Concepts

Octane Number

The octane number is a critical measure in the world of fuels, particularly gasoline. It indicates a fuel's ability to resist knocking, which is an undesirable effect in engines. Knocking happens when fuel burns unevenly in the engine cylinders, causing a knocking sound which can damage the engine.

A higher octane number signifies that the fuel is more resistant to knock. This means it can withstand more compression before it automatically ignites. Typically, regular gasoline has an octane number of about 87, while premium fuels are higher, often reaching 91 or more.

• Octane number is essential for engine performance.
• Higher octane numbers prevent engine knocking.
• It is a key parameter in choosing the right fuel for your vehicle.

Increases in octane numbers can be achieved by adding certain chemicals, like aromatic hydrocarbons, which we will discuss further.

Aromatic Hydrocarbons

Aromatic hydrocarbons are a special type of hydrocarbons that include benzene, toluene, and xylene, commonly known as BTX. These compounds have a unique ring-like structure that makes them highly stable, a hallmark of aromatic chemistry.

Aromatic hydrocarbons play a significant role in the chemical industry and as fuel additives. They are called 'aromatic' because many of these compounds have distinctive smells.

• Benzene, with the formula \(C_6H_6\), is the simplest aromatic hydrocarbon. It is known for its strong, sweet scent.
• Toluene, \(C_7H_8\), is another aromatic compound often used in paint thinners.
• Xylene, \(C_8H_{10}\), is used in the manufacture of certain plastics and as a solvent.

These compounds are effective in raising the octane number of gasoline, hence improving fuel performance.

Fuel Additives

Fuel additives are substances added to fuels to improve their properties and performance. They can optimize engine performance, clean engine parts, and reduce emissions.

Aromatic hydrocarbons, such as those in BTX, act as effective fuel additives by boosting the octane number. This makes the fuel more stable and enhances how the engine performs.

• Improved engine efficiency: This leads to better fuel economy.
• Reduced emissions: Additives can help decrease harmful emissions.
• Increased power: Fuels with added BTX can produce more power for the engine.

Understanding the role of fuel additives like BTX is crucial for those looking to maintain vehicle performance and reduce environmental impact.