Assertion:Electronegativity is not a measurable quantity.
Reason:The electronegativity of any given element is not constant,itvaries depending on the element to which it bound.

Options

A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct and Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

Answer

To solve the question regarding the assertion and reason about electronegativity, we can follow these steps:

### Step 1: Understand the Assertion
The assertion states that "Electronegativity is not a measurable quantity."
- Electronegativity is a concept that describes the tendency of an atom to attract electrons in a chemical bond. However, it is not a directly measurable quantity like mass or volume. Instead, it is often represented on a relative scale (such as the Pauling scale) based on comparisons between different elements.

### Step 2: Understand the Reason
The reason given is that "The electronegativity of any given element is not constant; it varies depending on the element to which it is bound."
- This statement is true because the electronegativity of an element can change based on the chemical environment and the other atoms it is bonded to. For example, the electronegativity of hydrogen can vary when it is bonded to different elements, as shown in the examples of sodium hydride (NaH) and water (H2O).

### Step 3: Analyze the Relationship Between Assertion and Reason
- Both the assertion and the reason are correct. The assertion correctly states that electronegativity is not a measurable quantity in absolute terms, while the reason explains why this is the case: electronegativity is not constant and can vary depending on the bonding context.

### Step 4: Conclusion
- Since both the assertion and reason are correct, and the reason provides a valid explanation for the assertion, the correct answer is that both the assertion and reason are correct, and the reason is the correct explanation for the assertion.

### Final Answer
Both the assertion and reason are correct, and the reason is the correct explanation for the assertion.

---