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.

(a) Which image represents the arrangement of molecules at 125 °C?

Video transcript

Hello everyone. So this problem, we're being told that 294.5 the compound right over here undergoes a phase transition from the crystalline solid phase to a liquid crystal phase. And now these four different diagrams here, we want to find the one that best represents the liquid crystal that's formed at 294.5 health. It's taking a look at answer choice. A right over here is automatically eliminated from our answer choices because we don't have a called sterile compound. And then if we scroll down a little here, answer choice D. Is also going to be eliminated because look at crystals having more ordered arrangements. We're being told in the problem that we do have liquid crystals, silver eliminate D. For that reason. And now comparing B and C. Then we have to get a little bit more technical. So we're being told that the temperature is 294.5, basically the temperature does not change. So it's as an initial temperature. So the compound remains at a crystalline solid, we're just going to be highly highly ordered. So taking a look at our illustration between B and C. We see that C. Is slightly disordered because of these little ends here, but B is perfectly in place. So between B and C. B best represents our liquid crystals. And answer choice. B is going to be my final answer for this problem