When dilute aqueous solution of KI (excess) is added to AgNO3 solution, the charge on the AgI colloidal, particles formed will be:

The correct option is: Positive

Dilute aqueous solution of potassium iodide (KI) in excess is added to silver nitrate (${\mathrm{AgNO}}_3$) solution.

When KI is added to ${\mathrm{AgNO}}_3$, a precipitation reaction occurs, forming silver iodide (AgI) precipitate according to the following chemical equation:
${\mathrm{Ag}}^{+}+I^{-}\Rightarrow \mathrm{AgI}\downarrow$

The colloidal particles of AgI have a property to preferentially adsorb common ions from the dispersion medium onto their surface to acquire a charge.

Here, ${\mathrm{AgNO}}_3$ is the dispersion medium and KI is added to it, but since ${\mathrm{AgNO}}_3$ is in the vessel and KI is added to it, the concentration of ${\mathrm{Ag}}^{+}$ ions from ${\mathrm{AgNO}}_3$ is initially present in the medium around the newly formed AgI particles. The AgI precipitate preferentially adsorbs the silver ions (${\mathrm{Ag}}^{+}$) which are common to its lattice.
This adsorption of positive silver ions (${\mathrm{Ag}}^{+}$) on the surface of the silver iodide precipitate gives it a positive charge:
$\mathrm{AgI}/{\mathrm{Ag}}^{+}$

Therefore, the charge on the AgI colloidal particles formed will be positive.