Problem 61 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following is used as an oxidizer in rocket propellents? (a) liquid hydrogen (b) nitric acid (c) liquid hydrazine (d) kerosene oil

Step-by-Step Solution

Answer

Nitric acid is used as an oxidizer in rocket propellants.

Step 1: Understanding Oxidizers and Fuels

In a rocket propellant system, there are two primary components: the oxidizer and the fuel. The oxidizer supplies the oxygen necessary for the fuel to burn. An oxidizer reacts with the fuel to produce thrust.

Step 2: Evaluate Each Option

Let's analyze each of the given options to determine which is an oxidizer: - **Liquid Hydrogen**: This is used as a fuel, not an oxidizer. - **Nitric Acid**: This can act as an oxidizer in various chemical reactions, including in rocket propellants. - **Liquid Hydrazine**: This is commonly used as a fuel. - **Kerosene Oil**: This is also used as a fuel in many engines.

Step 3: Identify the Oxidizer

Based on the evaluation: - Out of the given options, only **Nitric Acid** is used as an oxidizer in rocket propellents. - Liquid Hydrogen, Liquid Hydrazine, and Kerosene Oil are used as fuels.

Key Concepts

Oxidizers

In the world of rocket science, oxidizers are crucial substances that supply the necessary oxygen for fuel combustion. Unlike cars that rely on atmospheric oxygen to burn fuel, rockets require a separate oxygen source due to the vacuum of space. This is where oxidizers come into play. They allow the chemical reactions that propel rockets to occur by providing the oxygen atoms needed for combustion.
Common types of oxidizers used in rocket propellants include:

• Liquid oxygen (LOX)
• Nitric acid
• Nitrous oxide
• Hydrogen peroxide

Nitric acid, for instance, is sometimes used as an oxidizer in liquid propellant rockets. It reacts with fuels to produce hot gases that are expelled from the engine, thus producing thrust. Oxidizers are an essential part of the propellant system, as they enable the release of energy stored in the fuel, allowing the rocket to fly.

Fuels

Fuels are the second critical component in a rocket propellant system. They store chemical energy, which is released during combustion to propel the rocket forward. In rocket science, it's essential for fuels to be efficient and powerful to achieve the necessary thrust.
Some of the widely used fuels in rocket engines include:

• Liquid hydrogen
• Liquid hydrazine
• Kerosene
• Solid fuel mixtures

Liquid hydrogen, for example, is often paired with liquid oxygen to create a powerful chemical reaction. This combination is known for producing significant thrust due to the high energy release during combustion. Fuels are designed to react readily with oxidizers, and together, they form the basis of a rocket's propulsion system.

Chemical Reactions

Chemical reactions in rocket science are the driving force behind a rocket's ability to launch and reach space. When the oxidizer meets the fuel, a powerful reaction occurs, turning chemical potential energy into thermal energy. This process generates hot gases that expand rapidly and are expelled through the rocket's nozzles, creating thrust according to Newton's third law.
The basic chemical formula for a rocket's combustion might look like:a fuel (like hydrogen) + an oxidizer (like oxygen) \( \rightarrow \) water vapor + energyDuring this process, the energy released heats the reaction products, causing them to expand and push out of the rocket, propelling it in the opposite direction. Understanding these chemical reactions is crucial for designing efficient and powerful rocket engines.

Rocket Science

Rocket science is a field of engineering focused on the design, development, and operation of rockets. It involves understanding and applying principles from physics and chemistry to create vehicles capable of overcoming Earth's gravitational pull.
Key components of rocket science include:

• Propulsion systems
• Aerodynamics
• Materials engineering
• Guidance and control systems

Propulsion is central to rocket science, involving the strategic use of fuels and oxidizers to generate thrust. Engineers meticulously design propulsion systems to maximize efficiency and power. Rocket science also requires careful consideration of materials, as rockets endure extreme conditions during launch.
Rocket science is a complex and fascinating field, pushing the boundaries of what is technically possible and enabling humanity's exploration of space.