When 1 mL of toluene is added to 100 mL of benzene (bp 80.1 °C), the boiling point of the benzene solution rises, but when 1 mL of benzene is added to 100 mL of toluene (bp 110.6 °C), the boiling point of the toluene solution falls. Explain.

Video transcript

hi everyone for this problem it reads explain the following observations. Solution. One when two mL of cyclo hexane all is mixed with 200 mL of cyclo hexane. The boiling point of the cyclo hexane solution increases and solution to when two mL of cyclo hexane is mixed with 200 mL of cyclo hexane. All the cyclo hexane also solutions, boiling point decreases. So these are the two observations that we want to explain. So let's take a look at the first observation. Okay, so for the first observation we have cyclo hexane. All Okay and cyclo hexane all is non volatile. It's a non volatile salute. So when we have a non volatile salute, this is a collective property which means that there's going to be significant vapor pressure lowering. Okay and on the other hand, cyclo heck sane is a volatile salute. Okay, so we have a volatile salute and this is not a Colligan motive property. This is not a collective property and there's going to be more of inter molecular forces of attraction which means there's lower interactions and there's no not going to be a so significant vapor pressure lowering. So Alright, not significant vapor pressure, lower ring. So that's what we're looking at when we're talking about cyclo hexane. All and cyclo hexane. Okay, so this is referring to the cyclo hexane scene. It is a volatile salute and cyclo hexane. All is going to be the non volatile. Saw you. Okay so let's take a look at our answer choices what we want to look for is the answer choice. That explains this that cycle. Hexagonal is a non volatile Saw you that lowers the vapor pressure and increases the boiling point of the cyclo hexane solution. And then on the other hand, cyclo hexane is a volatile salute that increases the vapor pressure and decreases the boiling point of the cyclone external solution. So looking at our answer choices, answer choice A is going to be the one that clearly reflects those statements. Okay, that is it for this problem. I hope this was helpful.