The correct statement/s among the following is/are:

Options

1. AThe charge on the diffused layer of AgI colloidal solution by the addition of few drops of dilute aqueous solution of KI to an aqueous solution of $\mathrm{AgNO}_3$ is negative.
2. BThe charge on the diffused layer of AgI colloidal solution by the addition of few drops of dilute aqueous solution of $\mathrm{AgNO}_3$ to an aqueous solution of KI is positive.
3. CWhen the ionic strength of a colloidal solution is increased, thickness of the double layer is increased, and the colloid gets precipitated.
4. DWhen the ionic strength of a colloidal solution is increased, thickness of the double layer is decreased, and the colloid gets precipitated.