The charges on the colloidal $CdS$ sol and $TiO_2$ sol are,respectively :

Point out the false statement:

Given below are two statements:
Statement $I:$ In the coagulation of a negative sol,the flocculating power of the three given ions is in the order - $Al^{3+} > Ba^{2+} > Na^{+}$
Statement $II:$ In the coagulation of a positive sol,the flocculating power of the three given salts is in the order - $NaCl > Na_{2}SO_{4} > Na_{3}PO_{4}$
In the light of the above statements,choose the most appropriate answer from the options given below:

$Fe(OH)_3$ is a positively charged sol. For its precipitation, the best precipitating agent is:

Which one of the sol acts as a protective colloid?

Which of the following is an emulsifier?