Statement I: In the coagulation of a negative sol, the flocculating power of the three given ions is in the order - Al3+ > Ba2+ > Na+
Statement II: In the coagulation of a positive sol, the flocculating power of the three given salts is in the order - NaCl > Na2SO4 > Na3PO4
Choose the most appropriate answer from the options given below:
Statement I: In the coagulation of a negative sol, the flocculating power of the three given ions is in the order - Al3+ > Ba2+ > Na+
Statement II: In the coagulation of a positive sol, the flocculating power of the three given salts is in the order - NaCl > Na2SO4 > Na3PO4
Choose the most appropriate answer from the options given below:
- Both Statement I and Statement II are correct.
- Both Statement I and Statement II are incorrect.
- Statement I is correct but Statement II is incorrect.
- Statement I is incorrect but Statement II is correct.
The Correct Option is C
Solution and Explanation
To resolve the problem, we must evaluate the flocculating power of ions and salts based on their nature and the charge present. This involves understanding concepts related to the coagulation of sols in colloidal chemistry.
Statement I Analysis: In the coagulation of a negative sol, it is a well-established fact that the flocculating power of ions increases with an increase in charge. This follows from Hardy-Schulze rule, which states that the greater the charge on the flocculating ion, the greater its capacity to cause precipitation of the sol. Thus, the order of flocculating power given is correct: Al3+ (3+ charge) > Ba2+ (2+ charge) > Na+ (1+ charge).
Conclusion for Statement I: This statement is correct.
Statement II Analysis: In the coagulation of a positive sol, the flocculating ability of salts is again assessed based on the valency of the anions they provide. According to the Hardy-Schulze rule, higher valency anions have higher coagulation power. NaCl provides Cl- ions, Na2SO4 provides SO42- ions, and Na3PO4 provides PO43- ions. Thus, logically, the order should actually be: PO43- > SO42- > Cl-, which contradicts the given statement.
Conclusion for Statement II: This statement is incorrect.
Final Answer: Statement I is correct but Statement II is incorrect.
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Concepts Used:
Surface Chemistry
The study of the chemical phenomena that occur at the interface of two surfaces which can be solid-liquid, solid-gas, solid-vacuum, liquid-gas, etc.
Read Also: Surface Chemistry
Applications of surface chemistry are:
Adsorption:
The process of attraction and aggregation of the molecules of a substance on the surface of a solid is known as adsorption. For Example, N2 adsorbs on the surface of activated charcoal
Two types of adsorption are:-
- Chemisorption: It is also known as Chemical Adsorption.
- Physisorption: It is also known as Physical Adsorption.
Corrosion:
The process through which the refined metals convert themselves into more stable compounds is known as corrosion.
Crystallisation:
The type of technique used in order to purify the substances to separate Solids from liquids is known as crystallisation.
Heterogeneous Catalysis:
The process wherein a catalyst is used in order to increase the rate of a chemical reaction is known as catalysis. The catalyst does not undergo any transformation and can be recovered in a chemically unchanged state.
There are two types of catalysis:-
- When the catalyst involved and the reacting substances are same states of matter or in the same phase, it is known as Homogeneous Catalysis.
- When the catalyst involved and the reacting substances are in different states of matter or different phases, it is known as Heterogeneous Catalysis.