Soap with water forms :

[amp_mcq option1=”Metallotropic liquid crystal” option2=”Thermotropic liquid crystal” option3=”Homogeneous solution” option4=”Lyotropic liquid crystal” correct=”option4″]

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UPSC NDA-1 – 2024

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Soap with water can form lyotropic liquid crystals, especially at higher concentrations.

Soap molecules are amphiphilic, having a hydrophilic (water-attracting) head and a hydrophobic (water-repelling) tail. In water, they aggregate into structures like micelles, bilayers, or vesicles depending on concentration and temperature. These ordered structures often exhibit liquid crystalline phases, which are classified as lyotropic because their formation depends on the concentration of the solute (soap) in the solvent (water).

A homogeneous solution is formed at very low soap concentrations where molecules are dispersed individually. However, the characteristic behavior of soap forming micelles and other structured phases at higher concentrations leads to lyotropic liquid crystal phases. Thermotropic liquid crystals are formed by pure substances or mixtures that show liquid crystalline phases at different temperatures without a solvent. Metallotropic liquid crystals are formed from molten salts.

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