Which of the following is not negatively charged sol?

Step-by-step solution

Charge determination for colloidal systems Colloidal charge arises from preferential ion adsorption from solution or intrinsic molecular properties. The As ₂ S ₃ sol adsorbs sulfide ions ( S ²⁻ ) resulting in negative charge. Clay particles develop negative charge through isomorphic substitution ( Al ³⁺ Mg ²⁺ ) and surface hydroxyl dissociation. Congo Red, an anionic dye, forms negatively charged colloidal particles through adsorption of dye anions. Haemoglobin exhibits amphoteric behavior with isoelectric point ne