The Question is from neet-chemistry principles-related-to-practical-chemistry , and it was created by the author Mr. S M HUSSAIN

Question

The Krafft temperature of a surfactant is the temperature:

Mr. S M HUSSAIN · Accepted Answer

## CORE INFORMATION
✓ **Answer**: D
## CONCEPT FRAMEWORK
 **Primary Concept**: Krafft Temperature of Surfactants
 **Related Topics**: Micelle formation, Surfactant properties, Thermodynamics of micellization
 **Prerequisites**: Understanding of surfactants, micelles, and solubility.
## SOLUTION PATHWAY
**Given Information**:
The question asks for the definition of the Krafft temperature.
**Method & Steps**:
1. Understanding Surfactants and Micelles:
Surfactants are amphiphilic molecules, meaning they have both hydrophilic (water-loving) and hydrophobic (water-fearing) parts.  Above a certain concentration (critical micelle concentration or CMC), these molecules spontaneously aggregate into micelles in aqueous solutions.  This aggregation is driven by the hydrophobic effect, where the hydrophobic tails cluster together to minimize their contact with water, while the hydrophilic heads remain in contact with the surrounding water.
2. Defining Krafft Temperature:
The Krafft temperature ($T_K$) is the temperature above which the solubility of a surfactant increases sharply, enabling sufficient concentration to form micelles spontaneously. Below this temperature, the surfactant solubility is low, and micelle formation is not thermodynamically favorable.
3. Analyzing the Options:
Option A is incorrect because below the Krafft temperature, micelles are not stable due to low surfactant concentration. 
Option B is incorrect because at the Krafft temperature, the surfactant's solubility increases significantly, not becoming completely insoluble.
Option C is incorrect because surfactants don't decompose at their Krafft temperature.  Decomposition occurs at much higher temperatures.
Option D is correct because above the Krafft temperature, the solubility is high enough for spontaneous micelle formation to occur.
**Result**: The Krafft temperature is the temperature above which micelle formation becomes spontaneous.
**Verification**: The definition aligns with the thermodynamic principles governing micellization.
## OPTION ANALYSIS
A :x: Below the Krafft temperature, the concentration of surfactant is too low for micelle formation.
B :x: The Krafft temperature marks a significant increase in solubility, not complete insolubility.
C :x: Surfactant decomposition happens at much higher temperatures than the Krafft temperature.
D ✓: Above the Krafft temperature, the solubility is sufficient for spontaneous micelle formation.
## LEARNING AIDS
 **Common Mistakes**:
  1.Confusing Krafft temperature with CMC: CMC is the concentration at which micelles form, while Krafft temperature is the temperature at which sufficient solubility is reached for micelle formation.
  2.Misunderstanding the relationship between temperature and solubility:  Solubility generally increases with temperature, which is key to understanding the Krafft temperature.
 **Quick Tips**:
  1.Remember that Krafft temperature is about solubility enabling micellization, not the micellization process itself.
  2.Visualize the surfactant molecules aggregating into micelles above the Krafft temperature.

Mr. S M HUSSAIN · Answer

Below which micelles decompose

Mr. S M HUSSAIN · Answer

At which the surfactant becomes completely insoluble

Mr. S M HUSSAIN · Answer

Above which the surfactant decomposes

Mr. S M HUSSAIN · Answer

The correct Option is "Above which micelle formation becomes spontaneous"

NEET Chemistry Chemistry In Everyday Life MCQs

Select Topic

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

Question Tags

NEET Subjects

Our Bots

Company