Which of the following options is/are true w.r.t, surface phenomenon?

(symbols have their usual meaning)

At extremely low pressures, graph of $\log \frac{\mathrm{x}}{\mathrm{m}}$ versus log P for adsorption of gases over a solid will have unit slope.

On adding invertase to an aqueous solution of cane sugar the rate of inversion of specific optical rotation of the solution increases.

Metal sulphide sols are reversible sols.

On mixing 100 ml of0.1 M NaCl solution to 200 ml of 0.02 M $\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$ solution, a negatively charged sol will be obtained.