This is the answer to Chapter three. Problem number 45 from the Smith Organic Chemistry textbook. Ah, And in this problem, we're asked to compare tetrahydrocannabinol, which is the active ingredient in marijuana, um, to ethanol, which is the alcohol. That's, uh, you know, in beer, wine and hard liquor. Um, and so were asked, um, why, um, drug screenings are able to detect the presence of T h c, which is tetrahydrocannabinol. Ah, but not ethanol. Weeks after these substances have been introduced into the body. Um, okay. And so the answer here, um, is, uh, because of polarity. Eso ethanol has two carbons. Um, and one alcohol. One. Ohh. And so ethanol is very water soluble. Um, very water soluble. Ah, and so it is. It is rapidly passed into the urine, rapidly enters urine. Ah, and is rapidly urinated out. So, uh, several hours after a person stops consuming ethanol, they've urinated out all of the ethanol, and it's metabolites that were in their body. Um, and that again is because ethanol is so water soluble. So when we look at th see, what we see is that we have une ether here. Ah, and we have one alcohol here. Let me just make sure that I did redraw that correctly. Okay, Um and so there are only really two polar groups in this, uh, somewhat large T h c molecule. And so, based on the water soluble ity rules that we learned in this chapter, T h C is not water soluble. And so what ends up happening is it is soluble in organic solvents, Um, and so T h c enters the body and it ends up stored in fatty tissue. Um, because fatty tissue lipids, lipids, air able to sort of act as a solvent here and and dissolve the T h C. So T c is stored in fat. Ah, and then very slowly excreted over a period of weeks. And so that's why th see is detectable for up to 30 days after use. Whereas Effie no, um, you know, at 30 hours, you probably can't detect that someone. Someone used it 30 hours ago. This is also the reason that, um, tht extracts our oil based and not water based because th c is not water soluble. Um and so, uh, that's that's the way to approach this problem. We just need to consider soluble ity and then realize that polar ethanol is rapidly excreted in the urine, whereas very non polar water insoluble T C eyes stored in fat and takes much longer to slowly exit the body a little at a time. Ah, and so that's the answer to Chapter three. Problem number 45.