Question

Measuring Zeta potential is useful in determining which property of colloidal solution?

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Answer 1

By selective ​adsorption on the surface, a colloids acquire a positive or negative charge. The layer attracts a counter ion from medium to form a second layer​.

The combination of the two layers of opposite charges around the colloidal particle ​is known as Helmholtz electrical double layer​.

Here, the first layer ions is firmly held and second layer of ions is diffused layer​ and it is mobile.

As separation​ of charge ​results in potential, the charge of opposite sign on fixed and diffused part of double layer​ results in a potential difference​ known as Electrokinetic potential or zeta potential.​​

Greater the Zeta potential more will be the stability of colloidal particles as there will be a balance between the repulsive interactions between the charges of electrical double layer and attractive van der Waal interactions between molecules.

Hence, option (c) is correct.