Which of the following is not correct?

In the precipitation of soap,which can be used instead of $NaCl$?

Which of the following statements is true for a lyophobic sol?

Critical Micelle Concentration $(CMC)$ for a soap solution is $1.5 \times 10^{-4} \ mol \ L^{-1}$. Micelle formation is possible only when the concentration of soap solution in $mol \ L^{-1}$ is:

In the reaction $SO_{2(g)} + 2H_2S_{(g)} \rightarrow 3S_{(sol)} + 2H_2O_{(l)}$,which method is used to obtain the sulfur sol?

Which one of the following statements is not correct?