Kevlar can be made by reacting 1,4-diaminobenzene, \({{\text{H}}_{\text{2}}}{\text{N}}{{\text{C}}_{\text{6}}}{{\text{H}}_{\text{4}}}{\text{N}}{{\text{H}}_{\text{2}}}\), with 1,4-benzenedicarbonyl chloride, \({\text{ClOC}}{{\text{C}}_{\text{6}}}{{\text{H}}_{\text{4}}}{\text{COCl}}\). Write the equation for the reaction of n molecules of 1,4-diaminobenzene reacting with n molecules of 1,4-benzenedicarbonyl chloride.

Kevlar is an example of a lyotropic liquid crystal. Outline what is meant by lyotropic liquid crystal.

correct products;

correctly balanced;

liquid crystals:

fluids with properties that depend on the molecular orientation relative to a fixed axis;

lyotropic:

solutions that show the liquid-crystal state at certain concentrations;

Few candidates could give the correct equation to produce Kevlar, though some scored 1 mark for giving the correct products.

The concept of liquid crystals was not understood by many. Very few mentioned that lyotropic is a solution.