Problem 11 - A Complete Resource Book in Chemistry for JEE Main

Question

The element used for carrying out the nuclear reaction is (a) Thorium- 232 (b) Uranium-238 (c) Plutonium-239 (d) Neptunium- 293

Step-by-Step Solution

Answer

Plutonium-239 (c) is used for nuclear reactions.

Step 1: Understanding Nuclear Reactions

To determine which element is used to carry out a nuclear reaction, we need to understand that nuclear reactions often involve isotopes that are fissile or fertile. Fissile materials, like Uranium-235 and Plutonium-239, can sustain a nuclear chain reaction.

Step 2: Identify Common Elements for Nuclear Reactions

Commonly used elements in nuclear reactors for chain reactions are Uranium-235 and Plutonium-239. Fertile materials like Uranium-238 and Thorium-232 absorb neutrons to become fissile isotopes.

Step 3: Evaluate the Given Options

Review the options given: Thorium-232, Uranium-238, Plutonium-239, and Neptunium-293. Plutonium-239 is known as a fissile material commonly used in nuclear reactions, while the others play different roles or are less commonly used directly for sustaining nuclear chain reactions.

Step 4: Choose the Correct Element

Given the information and common usage in nuclear reactors, Plutonium-239 is the element from the list that is typically used to carry out a nuclear reaction because it is fissile and can sustain a nuclear chain reaction.

Key Concepts

Fissile Materials

Fissile materials are crucial elements in the world of nuclear reactions. These materials have the unique ability to sustain a nuclear chain reaction. What makes a substance fissile is its capability to capture a slow-moving neutron and subsequently undergo fission, releasing energy in the process.
Some well-known fissile materials include:

• Uranium-235
• Plutonium-239
• Uranium-233

As a neutron interacts with a fissile material, it causes the nucleus of the atom to split. This process releases a significant amount of energy along with additional neutrons, which can trigger further reactions. To identify fissile materials, scientists often look at the material's ability to undergo fission upon capturing a neutron. This feature is pivotal for both nuclear power production and nuclear weapon design. It's important to understand that not all nuclear materials can sustain chain reactions; only fissile ones possess such capabilities.

Plutonium-239

Plutonium-239 is one of the most significant fissile materials used in nuclear technology. Discovered in the 1940s, it has since been utilized as both an energy source and a component in nuclear weapons. This isotope of plutonium is capable of maintaining a sustained nuclear chain reaction, which is why it is so valuable. To produce Plutonium-239, Uranium-238 is typically bombarded with neutrons in a reactor. The Uranium-238 absorbs the neutrons, eventually transforming into Plutonium-239 through a series of nuclear reactions.
Some key uses and characteristics include:

• Used as fuel in reactors and in the production of nuclear weapons.
• Exhibits a high rate of neutron-induced fission.
• Poses serious safety and security challenges due to its long half-life and radioactive properties.

Because of its powerful ability to drive chain reactions, handling and regulation of Plutonium-239 involve stringent safety protocols, making it a focal point in discussions about nuclear proliferation.

Uranium Isotopes

Uranium isotopes are among the most widely recognized components involved in nuclear reactions. The most common isotopes are Uranium-238 and Uranium-235. Each isotope has different characteristics and roles in nuclear technology. **Uranium-238**

• Accounts for about 99.3% of natural uranium.
• Is not fissile but fertile, meaning it can be converted into fissile material, such as Plutonium-239.
• Typically used in breeder reactors to produce more fissile material.

**Uranium-235**

• Comprises only about 0.7% of natural uranium.
• Fissile by nature; it can sustain chain reactions easily.
• Commonly enriched for use in nuclear reactors and weapons.

In nuclear power plants, Uranium-235 is often enriched from its natural proportion to increase the fuel's efficiency and sustain long-term reactions. Understanding the roles and properties of different uranium isotopes helps in harnessing nuclear technology effectively and safely.