Name a thermotropic liquid crystal.

Describe the meaning of the term liquid crystals. State and explain which diagram in figure $11, \mathrm{a} \mathrm{or} \mathrm{b},$ represents molecules that are in a liquid crystalline phase.

The structure of $4-$pentyl$-4-$cyanobiphenyl, a commercially available nematic crystalline material used in electrical display devices, is shown in figure $12$.

Describe and explain in molecular terms the workings of a twisted nematic liquid crystal.

Compare the positional and directional order in a crystalline solid, a nematic phase liquid crystal, and a pure liquid. Show your answer by stating yes or no in a copy of table $1$.