Question

why is salt used to make colloids settle.Can we use something else instead of it ?

Answer 1

Dear student!

We know that, colloidal particles are charged but due to the presence of two opposite and equal charges in the dispersed phase and dispersion medium, they behave as electrically neutral.

Now, adding salts to a colloid can provide charged ions that surround charged solid particles and neutralize the repulsion. This allows them to bind together into particles which make them too large to remain as colloids, and they settle down.

This can not be done by other chemicals as the salt have both the cations and anions which may be separated in the solutions.