Which chemical compound, with the chemical formula CH₃CH₂Cl, is used as a blowing agent in foamed plastics?

Chloroethane

The correct answer is option 4. Chloroethane.

Chloroethane, also known as ethyl chloride, is a chemical compound with the formula \(CH_3CH_2Cl\). It is a colorless, flammable gas at room temperature and pressure, but it can also be compressed into a liquid for storage and transportation. Chloroethane is widely used as a blowing agent in the production of foamed plastics.

As a blowing agent, chloroethane serves the purpose of creating gas bubbles within the plastic matrix during the foaming process. These gas bubbles impart a characteristic lightweight and porous structure to the foam, making it suitable for various applications such as insulation, packaging, and cushioning materials.

During the manufacturing process of foamed plastics, chloroethane is typically mixed with the plastic resin before it undergoes heating or chemical reactions that cause it to expand and form a foam. When the temperature or pressure is increased, chloroethane vaporizes and forms gas bubbles within the plastic, resulting in a foamed structure.

Chloroethane is favored as a blowing agent due to its relatively low boiling point, which allows it to vaporize readily at typical processing temperatures. Additionally, it is compatible with various plastic resins and does not react chemically with them, ensuring that the foam's properties remain stable.

However, it's worth noting that the use of chloroethane as a blowing agent has declined in recent years due to environmental and health concerns associated with chlorinated compounds. In many applications, it has been replaced with alternative blowing agents that have less impact on the environment and human health.