Question

Choose the incorrect statement among the following about the metal sulphide ions:

• A. The solution particles are positively charged due to preferential adsorption of metal ions
• B. The solution particles are negatively charged due to preferential adsorption of sulphide ions
• C. $M{g}^{2+}$ will coagulate the sol more efficiently compared to $N{a}^{+}$
• D. The solution need stabilising agents for their preservation

Answer 1

The correct option is A The solution particles are positively charged due to preferential adsorption of metal ions

The charge on colloidalsolution is due to the preferential adsorption of either positive or negative ions on their surface. Metal sulphide solution is negatively charged due to preferential adsorption of sulphide ions.

Coagulation is brought by the ions having opposite charges to that of the solution. Since this sol is negatively charged hence it can be coagulated by cations. Again efficacy of an ion to cause coagulation depends upon its valency. Thus $M{g}^{2+}$ will coagulate the sol more efficiently compared to $N{a}^{+}$

The metal sulphide solutions being lyophobic solution need stabilizing agents for preservation.