Question

(a) What is the difference between chlorofluorocarbons and hydrofluorocarbons? (b) Why are hydrofluorocarbons potentially less harmful to the ozone layer than CFCs?

Short answer

The main difference between chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs) is the presence of chlorine in CFCs and hydrogen in HFCs. CFCs can break down in the stratosphere, releasing chlorine atoms, which catalyze reactions that deplete the ozone layer. In contrast, HFCs do not contain chlorine and do not contribute to ozone depletion. However, they are potent greenhouse gases and contribute to global warming.

Step-by-step solution

Defining Chlorofluorocarbons (CFCs) and Hydrofluorocarbons (HFCs)

Chlorofluorocarbons (CFCs) are types of compounds that are made up of carbon, chlorine, and fluorine atoms. Hydrofluorocarbons (HFCs), on the other hand, are composed of hydrogen, fluorine, and carbon atoms.

Differentiating between Chlorofluorocarbons (CFCs) and Hydrofluorocarbons (HFCs)

The fundamental difference between these two groups of compounds is the presence of chlorine in CFCs and hydrogen in HFCs. This variation in their composition results in different chemical properties and environmental impacts.

Understanding the Environmental Impact of Chlorofluorocarbons (CFCs)

CFCs are very stable in the lower atmosphere and thus do not break down easily. However, when they rise to the stratosphere (upper atmosphere), they can be broken down by solar radiation, releasing chlorine atoms. These chlorine atoms are capable of catalyzing reactions that deplete the ozone layer, a region of the atmosphere that blocks the majority of the sun's harmful ultraviolet radiation.

Understanding the Environmental Impact of Hydrofluorocarbons (HFCs)

Unlike CFCs, HFCs do not contain chlorine and thus do not contribute to ozone depletion when they break down in the stratosphere. Therefore, they are considered less harmful to the ozone layer. However, it's important to note that despite the fact that HFCs do not harm the ozone layer, they are potent greenhouse gases that can contribute significantly to global warming. As a result, their use is also being phased down internationally.