ABSTRACT
The viscosity could increase or decrease as per interactions of the solvents. The viscosity of water as a solvent is 0.8903 mPa.s, which is noted as reference or standard data. If the viscosity of a solution is increased on adding salts, the B or [η] is positive and the salt is the structure maker, and if the same is decreased, then the solute is the structure maker. The ionic solvation of the ions causes a positive charge on the outer surface of the cationic solvation sphere and a negative charge on the anionic solvation sphere. Such alignment of opposite charges of solvation spheres leads to strengthening of the cohesive force (CF), with a higher surface tension as well as viscosity. A separate mechanism is applied for salts and surfactants. In the case of salts, ionic hydration around ions occurs with a stronger ionic field, which strengthens the CF between newly aligned water molecules around oppositely charged ions.
