Question

Freons are not recommended to be used in refrigerators because they (a) cause global warming (b) cause acid rain (c) cause depletion of ozone layer (d) cause very less cooling.

Short answer

Freons are not recommended for use in refrigerators because they cause depletion of the ozone layer.

Step-by-step solution

Identify the Environmental Impact of Freons

Determine which environmental issue is associated with the use of Freons. Freons, which are chlorofluorocarbons (CFCs), have been identified to cause a specific type of environmental harm that affects the atmosphere.

Understand the Effects of Freons

Review the known effects of Freons on the environment. These substances are known to contribute significantly to one of the listed environmental issues, which has been a subject of major environmental concern and scientific research.

Select the Correct Option

Choose the option that correctly identifies the environmental problem caused by Freons. The most recognized impact of Freons in the atmosphere is the depletion of the ozone layer. Therefore, the correct option is (c) cause depletion of ozone layer.

Key concepts

Ozone Layer Depletion

The ozone layer is a crucial shield in the Earth's stratosphere that absorbs the majority of the sun's harmful ultraviolet (UV) radiation. When Freons, which are a group of chemicals known as chlorofluorocarbons (CFCs), are released into the atmosphere, they eventually rise to the stratosphere. Here, the sun's UV radiation breaks down these CFCs, releasing chlorine atoms.

These chlorine atoms are highly reactive and have the ability to break down ozone molecules. A single molecule of chlorine can destroy over 100,000 ozone molecules before it is removed from the stratosphere. The result is a thinning of the ozone layer, known as ozone depletion, which leads to increased UV radiation reaching the Earth's surface. This rise in UV exposure can increase the risk of skin cancer, cataracts, and other health problems, as well as damage to the environment, including marine ecosystems and plant life.

International efforts like the Montreal Protocol have aimed to reduce the production and release of CFCs and have had significant success, but full recovery of the ozone layer will take many decades due to the long lifespan of CFCs in the atmosphere.

Chlorofluorocarbons (CFCs)

Chlorofluorocarbons, commonly known as CFCs, are synthesized compounds initially used widely in refrigeration, air conditioning, foam blowing, and as propellants in spray cans. They were favored for their stability, non-flammability, and low toxicity.

However, these same stable properties make CFCs persist in the atmosphere for a long time. Once CFCs reach the stratosphere, they are broken down by UV radiation, releasing chlorine atoms that contribute to the destruction of the ozone layer, as previously mentioned. In addition to ozone depletion, CFCs are also greenhouse gases, trapping heat in the Earth's atmosphere and contributing to global warming,

which has pervasive effects on global climates and ecosystems. Recognizing the adverse environmental impacts of CFCs has led to stringent regulations and a phase-out plan under the Montreal Protocol, a testament to global cooperation in environmental policy.

Global Warming

Global warming refers to the long-term increase in Earth's average surface temperature due to human activities, mostly the release of greenhouse gases like carbon dioxide, methane, nitrous oxide, and including CFCs. It's a central aspect of climate change, which also encompasses shifts in weather patterns, extreme events, and rising sea levels.

Greenhouse gases like CFCs trap heat in the atmosphere, preventing it from escaping into space, much like the glass of a greenhouse. This trapped heat leads to an increase in temperatures globally, which in turn causes ice caps and glaciers to melt, sea levels to rise, and extreme weather events to become more frequent and intense.

Although CFCs have been largely phased out because of their impact on the ozone layer, their contribution to global warming is noteworthy due to their high global warming potential (GWP). The GWP is a measure of how much heat a greenhouse gas traps in the atmosphere compared to carbon dioxide. CFCs, with their high GWP, can trap thousands of times more heat per unit mass than carbon dioxide.