Who introduced the concept of $Gold \ Number$?

Give information about the applications of colloids.

Statement $I:$ For colloidal particles,the values of colligative properties are of small order as compared to values shown by true solutions at the same concentration.
Statement $II:$ For colloidal particles,the potential difference between the fixed layer and the diffused layer of opposite charges is called the electrokinetic potential or zeta potential.
In the light of the above statements,choose the correct answer from the options given below.

The most effective coagulating agent for antimony sulphide sol is

Which of the following can form ionic micelles in water?

$10 \ mL$ of $0.5 \ M$ $NaCl$ is required to coagulate $1 \ L$ of $Sb_2S_3$ sol in $2$ hours. The flocculating value of $NaCl$ (in millimoles) is: