The following compound undergoes a phase transition from the solid to the smectic liquid crystal phase at 121 °C. Upon further heating, the compound undergoes another transition to liquid phase at 131 °C.

(b) Which image represents the arrangement of molecules at 135 °C?

Video transcript

Hello everyone. So in this video we're being told that 294.5 Kelvin's, the compound right over here undergoes a phase transition from the crystalline solid phase to a liquid crystal phase. So when you increase the temperature to 306.5 Kelvin's, it undergoes another liquid crystal phase transition. So after these four different diagrams that were given, we want to find that one that best represents the liquid crystal was formed at 306.5 Kelvin's. So, taking a look at answer choice A here, this is not one of our answers and that's because we don't have a call serial compound. And then for answer choice D. Here, this is also not one of our choices. And the reason being is that because our liquid crystals are definitely more organized than this here. So liquid crystals are more ordered. All right. So that leaves us between answer choices B&C. So comparing other choices B&C. Here, then we have to get more technical. So, the problem tells us that the compound is when it's heated to directed 6. Kelvin's, that the molecules become less ordered. So Mark your become more disordered. When temperature rises in between this excess choice. Be here and see we see that here is just perfectly ordered, but C. Is just slightly disordered. And because of that, our final answer choice is going to be seen where it's slightly disordered