Question

Compare the natures and extents of order in the smectic liquid-crystal and isotropic liquid phases of a substance. Which has the higher entropy? Which has the higher enthalpy?

Short answer

The isotropic phase has the higher entropy and higher enthalpy.

Step-by-step solution

Smectic liquid-crystals

Smectic is related to soap. Smectic phase is a phase that shows in liquid-crystal molecules. It shows a translational order degree and maintains the orientation order. Moreover, its alignment is in layers or planes. When the order increases, it acts as a solid.

Isotropic liquid phases

A liquid having all its properties are uniform in all directions is known as isotropic liquid phases. In these phases, the molecules are constantly random in motion.

Hence, the isotropic phase has higher enthalpy and higher entropy.