Question: The charges on the colloidal $\mathrm{CdS}$ sol and $\mathrm{TiO}_{2}$ sol are, respectively :
positive and positive
positive and negative
negative and negative
negative and positive
Correct Option: , 4
Solution:
CdS sol $\rightarrow-$ ve sol
$\mathrm{TiO}_{2}$ sol $\rightarrow+$ ve sol
