Question

Would you expect the substance \(\mathrm{CFBr}_{3}\) to be effective in depleting the ozone layer, assuming that it is present in the stratosphere? Explain.

Short answer

Yes, the substance \(\mathrm{CFBr}_{3}\) would likely be effective in depleting the ozone layer if present in the stratosphere, due to its chemical structure and properties. It shares some properties with known ozone-depleting substances like CFCs and halons, as it contains a reactive halogen (bromine) and can initiate a catalytic cycle in which ozone molecules are converted into oxygen gas.

Step-by-step solution

Identify the structure of the compound

First, let's identify the structure of the compound \(\mathrm{CFBr}_{3}\). It has one carbon atom, three fluorine atoms, and one bromine atom. The compound is a halogenated hydrocarbon like CFCs and halons.

Analyze the chemical properties of the compound

Now, let's analyze the chemical properties of the compound \(\mathrm{CFBr}_{3}\). Like CFCs, it contains a halogen atom (in this case, bromine) which is highly reactive. Bromine atoms, after being released in the stratosphere, can undergo a series of reactions with ozone which could lead to the depletion of the ozone layer. _Particularly_, the reaction starts when the \(\mathrm{CFBr}_{3}\) molecules absorb ultraviolet light from the sun and dissociate into reactive species, like \(\mathrm{CF}_{3}\) and \(\mathrm{Br}\). After this, the reactive bromine atom can react with an ozone molecule (\(\mathrm{O}_{3}\)), and convert it into oxygen gas (\(\mathrm{O}_{2}\)) through a catalyst cycle: \[1.\: \mathrm{Br} + \mathrm{O}_3 \rightarrow \mathrm{BrO} + \mathrm{O}_2\] \[2.\: \mathrm{BrO} + \mathrm{O} \rightarrow \mathrm{Br} + \mathrm{O}_2\] The net effect of these reactions is the conversion of one ozone molecule and one atomic oxygen into two oxygen gas molecules: \[\mathrm{O}_3 + \mathrm{O} \rightarrow 2 \mathrm{O}_2\] In this process, the bromine atom acts as a catalyst, as it is not consumed in the reaction and can repeatedly participate, thus depleting a significant amount of ozone molecules.

Compare with known ozone-depleting substances

When comparing \(\mathrm{CFBr}_{3}\) to known ozone-depleting substances, we observe that it shares some properties with CFCs and halons. Like these compounds, it contains a halogen that is highly reactive and could initiate a catalytic cycle by releasing bromine atoms in the stratosphere, leading to ozone depletion.

Conclude whether CFBr3 would be effective in ozone depletion

Based on the chemical structure and reactions involving \(\mathrm{CFBr}_{3}\), we can conclude that, if present in the stratosphere, it would be effective in depleting the ozone layer due to the presence of a reactive halogen (bromine) in its structure and its potential to initiate a catalytic cycle involving ozone molecules.