Assertion (A): Micelles are formed by surfactant molecules above the critical micellization concentration `(CMC)` .
Reason(R): The conductivity of a solution having surfactant molecules decreases sharply at the `CMC` .
(a)If both (A) and (R) are correct, and (R) is the correct explanation of (A).
(b)If both (A) and (R) are correct, but (R) is not the correct explanation of (A).
(c)If (A) is incorrect, but (R) is correct.
(d)If both (A) and (R) are incorrect.
Assertion (A): Micelles are formed by surfactant molecules above the critical micellization concentration `(CMC)` .
Reason(R): The conductivity of a solution having surfactant molecules decreases sharply at the `CMC` .
(a)If both (A) and (R) are correct, and (R) is the correct explanation of (A).
(b)If both (A) and (R) are correct, but (R) is not the correct explanation of (A).
(c)If (A) is incorrect, but (R) is correct.
(d)If both (A) and (R) are incorrect.
Reason(R): The conductivity of a solution having surfactant molecules decreases sharply at the `CMC` .
(a)If both (A) and (R) are correct, and (R) is the correct explanation of (A).
(b)If both (A) and (R) are correct, but (R) is not the correct explanation of (A).
(c)If (A) is incorrect, but (R) is correct.
(d)If both (A) and (R) are incorrect.
A
If both (A) and (R) are correct, and (R) is the correct explanation of (A).
B
If both (A) and (R) are correct, but (R) is not the correct explanation of (A).
C
If (A) is incorrect, but (R) is correct.
D
If both (A) and (R) are incorrect.
Text Solution
AI Generated Solution
The correct Answer is:
To solve the question, we need to analyze the assertion and the reason provided and determine their validity and relationship.
### Step-by-Step Solution:
1. **Understanding the Assertion (A)**:
- The assertion states that "Micelles are formed by surfactant molecules above the critical micellization concentration (CMC)."
- This statement is **true**. Micelles are indeed formed when surfactant molecules aggregate above a certain concentration known as the CMC. Below this concentration, surfactant molecules remain dispersed in the solution.
2. **Understanding the Reason (R)**:
- The reason states that "The conductivity of a solution having surfactant molecules decreases sharply at the CMC."
- This statement is also **true**. When surfactant molecules aggregate to form micelles, the number of free ions in the solution decreases, leading to a reduction in conductivity. Before reaching the CMC, the ions are free to move, contributing to higher conductivity.
3. **Analyzing the Relationship**:
- Although both statements are correct, the reason does not explain why micelles are formed. The formation of micelles is due to the aggregation of surfactant molecules, while the decrease in conductivity is a consequence of this aggregation, not the cause of it.
4. **Conclusion**:
- Since both the assertion and reason are correct, but the reason does not correctly explain the assertion, the correct option is:
- **(b) If both (A) and (R) are correct, but (R) is not the correct explanation of (A).**
To solve the question, we need to analyze the assertion and the reason provided and determine their validity and relationship.
### Step-by-Step Solution:
1. **Understanding the Assertion (A)**:
- The assertion states that "Micelles are formed by surfactant molecules above the critical micellization concentration (CMC)."
- This statement is **true**. Micelles are indeed formed when surfactant molecules aggregate above a certain concentration known as the CMC. Below this concentration, surfactant molecules remain dispersed in the solution.
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