(a) Place the following substances in order of increasing volatility: CH₄, CBr₄, CH₂Cl₂, CH₃Cl, CHBr₃, and CH₂Br₂. (b) How do the boiling points vary through this series? (c) Explain your answer to part (b) in terms of intermolecular forces.

Video transcript

Hey everyone, we're asked to consider the following compounds and to arrange in order of increasing volatility and to briefly explain our answer. Now, looking at these compounds, we can see that they are all non polar substances, which means that the inter molecular force present here is going to be our London dispersion forces. Now, how does this relate to volatility? Well, we know that if a compound is more volatile, this means that it has weaker London dispersion forces. So in order to answer this question, we need to look at the strength of our inner molecular forces and in this case it will be our London dispersion forces. So to compare the strength, we will have to look at the molecular weight of each compound and the relation to this is that the smaller the molecular weight, the weaker our London dispersion forces are going to be Now in comparison to a larger molecular weight. This means our London dispersion forces are going to be stronger and that is because we have a more polarized able electron cloud. Now to arrange this in order of increasing volatility, the one that will be the least volatile will have the strongest London dispersion forces, which means it will have the largest molecular weight in this case it'll be carbon tetra I died followed by carbon tetra bromide. Next we will have carbon tetrachloride followed by carbon tetra fluoride. And lastly with the weakest London dispersion forces is going to be our methane and this is going to be our final answer. Now, I hope that made sense. And let us know if you have any questions.