Question

Which of the following colloids can be coagulated by $A{l}^{3+}$?

• A. Haemoglobin.
• B. $Ti{O}_2$
• C. $A{s}_2{S}_3$
• D. $CdS$

Answer 1

Answer: (C), (D)

$CdS$

$A{l}^{3+}$ is positively charged. Positively charged ion can coagulate negatively charged colloids.
Out of the given options $A{s}_2{S}_3$ and $CdS$ are negatively charged colloids.