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SnO_(2) forms a positively charged colloidal sol in acidie medium and a negatively charged sol in the basic medium. Why ? Explain . |
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Answer» Solution :`SnO_(2)` is ampotericin nature. It reacts with ACID, e.g, with HCL to form `SnCl_(4)` in the solution. The common `Sn^(4+)` ions are adsorbed on the SURFAC of `SnO_(2)` particles thereby giving them a positive charge `SnO_(2)+4HCl to SnCl_(4)+2H_(2)O` `SnO_(2)+Sn^(4+)to underset("POSITIVELY charged colloidal particles")([SnO_(2)]:Sn^(4+))` `SnO_(2)` reacts with a base, e.g., NaOH to form sodium stannate `(Na_(2)SnO_(3))` in the solution. The stannate ions are adsorbed on the surface of `SnO_(2)` particles giving them an negative charge. `SnO_(2)+2NAOH to underset("Sodium stannate")(Na_(2)SnO_(3)+)H_(2)O` `SnO_(2)+SnO_(3)^(2-)to underset("Negatively charged colloidal particles")([SnO_(2)]:SnO_(3)^(2-))` |
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