Name: Uses of Adsorption
Uploaded: 2019-07-19
Duration: 2 min 48 s
Description: Do you know how gas masks work? How does a perfume scent stick to us for long hours? It's all possible due to adsorption. Isn't it interesting? Learn more.

Question

Explain the terms Helmholtz electrical double layer and zeta potential. What are their significances in the colloidal solutions ?

Accepted Answer

The layer of positive or negative charge acquired by selective adsorption of Ions on the surface of a colloidal particle attracts Ions of opposite charge from the medium forming a second layer

$Agl / I^{-} K^{+} Agl / {Ag}^{+} I^{-}$

The combination of the two layers of opposite charges around the colloidal particle is called Helmholtz electrical double layer. Separation of charge ls the seat of potential, the charges of opposite signs on the fixed and diffused parts of the double layer results In a difference in potential between these layers. This potential difference between the fixed layer and the diffused layer of opposite charge ls called the electrokinetic potential or zeta potential. $[£]$

The presence of equal and similar charges on colloidal particles are largely responsible In providing stability to the colloidal solution. The repulsive forces between the charged particles having same charge prevent them from coalescing or aggregating when they come closer to one another.

Explain the terms Helmholtz electrical double layer and zeta potential. What are their significances in the colloidal solutions ?

Important Questions on Surface Chemistry

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