A colloidal solution of Agl is positively charged when prepared from a solution containing excess of `Ag^(+)` ions and negatively charged when prepared from a solution containing excess of `I^(-)` ions Explain.

Explanation

When a dilute `AgNO_(3)` solution is added to a dilute KI solution taken in excess, the precipitated AgI adsorbs `I^(-)` ions present in excess and a negatively charged Agl colloidal solution is formed. However when dilute KI solution is added to dilute `AgNO_(3)` solution taken in exces.s, Agl precipitate adsorbs `Ag^(+)` ions present in excess and a positively charged Agl colloidal solution is formed. Generally the ion common to dispersed particle is adsorbed.
`underset("Negatively charged")(AgI//I^(-))" "underset("Positively charged")(AgI//Ag^(+))`.