Question

Freon-12 is commonly used as (a) refrigerant (b) a solvent (c) insecticide (d) a fire extinguisher

Short answer

Freon-12 is commonly used as a refrigerant.

Step-by-step solution

Identify the Properties of Freon-12

Freon-12 is a chlorofluorocarbon (CFC) compound also known as dichlorodifluoromethane. This compound is well-known for its use in refrigeration and air conditioning systems due to its ability to vaporize at low temperatures.

Apply Contextual Knowledge

Consider the methods of application of Freon-12. Since it is favored for its cooling properties in various systems, its primary use aligns with the function as a refrigerant. It is generally not used as a solvent, insecticide, or fire extinguisher.

Determine the Common Usage

Based on the identified properties of Freon-12 and its compatibility with cooling applications, it is most commonly used as a refrigerant, making option (a) the correct choice.

Key concepts

Chlorofluorocarbon (CFC)

Chlorofluorocarbons, commonly abbreviated as CFCs, are a class of chemical compounds comprising carbon, chlorine, and fluorine atoms. These were first developed in the early 20th century as promising compounds due to their stability and non-flammability. Because of these attributes, CFCs found widespread use in various industrial applications.

One of the primary utilizations of CFCs was as refrigerants, but they were also used in aerosol propellants and foam blowing agents. Despite their utility in these fields, it quickly became evident that CFCs were damaging to the environment. When released into the atmosphere, they eventually rise up to the stratosphere, where they are broken apart by ultraviolet radiation. This process releases chlorine atoms, which contribute significantly to the depletion of the ozone layer.

To combat this threat, international agreements like the Montreal Protocol have been established, aiming to phase out the production and use of CFCs worldwide. Substitutes with lesser environmental impact are being used today while scientists and industries continue to search for more sustainable solutions.

Refrigerant

In the realm of cooling technology, a refrigerant is a critical substance that utilizes its ability to absorb heat in the environment and provide cooling. This is essentially the fluid that cycles through refrigerators, air conditioners, and freezers to facilitate the cooling process.

Refrigerants work by changing states—usually from a liquid to a gas and back again—absorbing and releasing heat in the process. As the refrigerant evaporates, it absorbs heat from its surroundings, leading to a cooling effect. Later, when it condenses back to liquid form, it releases the absorbed heat, usually outside the confines of the refrigerator or conditioning system.

Different types of refrigerants have been used over the years, with varying levels of efficiency and environmental impact. CFCs like Freon-12 were traditionally favored for their reliability in this role, as they are highly effective at changing states at the temperatures required for cooling applications. However, due to environmental concerns, the industry is now increasingly relying on alternatives such as hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs).

Dichlorodifluoromethane

Dichlorodifluoromethane is more commonly known by its trade name, Freon-12. It falls under the category of chlorofluorocarbons (CFCs), which were widely used in the past due to their stability, non-flammability, and effectiveness in refrigeration systems.

Freon-12's chemical composition, denoted as CCl₂F₂, enabled it to excel particularly as a refrigerant, due to its efficient thermal heat exchange capabilities and low boiling point. It was highly valued in air conditioning and refrigeration systems throughout the latter half of the 20th century.

However, this compound contributed significantly to the degradation of the ozone layer, leading to its eventual phase-out under international agreements. As a result, the utilities that depended on Freon-12 have been switching to more environmentally friendly alternatives. The changes underline the ongoing necessity to balance efficiency with environmental health, promoting continual advancements in chemical applications.