At the critical micelle concentration $(CMC)$,..........

Milk is an example of

Identify the incorrect statement.

Given below are two statements:
Statement $I :$ Emulsions of oil in water are unstable and sometimes they separate into two layers on standing.
Statement $II :$ For stabilisation of an emulsion,excess of electrolyte is added.
In the light of the above statements,choose the most appropriate answer from the options given below:

The concentration of electrolyte required to coagulate a given amount of $As_2S_3$ sol is minimum in the case of

Why does leather get hardened after tanning?