In the following questions, a statement of assertion (A) is followed by a statement of reason (R )
A : H-F forms stronger hydrogen bond than `H_(2)` O.
R : F is more electronegative than oxygen.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements , then mark (4).

Answer

To analyze the given assertion (A) and reason (R), we will break down the statements and evaluate their truthfulness and the relationship between them.

### Step 1: Evaluate the Assertion (A)
**Assertion (A): H-F forms stronger hydrogen bonds than H2O.**

- Hydrogen bonding occurs when a hydrogen atom is covalently bonded to a highly electronegative atom (like F, O, or N) and is attracted to another electronegative atom.
- HF (hydrogen fluoride) does indeed form hydrogen bonds. However, H2O (water) is known for its strong hydrogen bonding capabilities due to its ability to form multiple hydrogen bonds.
- In H2O, each molecule can form hydrogen bonds with four neighboring water molecules due to the two hydrogen atoms and two lone pairs on the oxygen atom.
- In contrast, HF can only form hydrogen bonds with two other HF molecules.
- Therefore, while HF does form hydrogen bonds, the assertion that HF forms stronger hydrogen bonds than H2O is **false**.

### Step 2: Evaluate the Reason (R)
**Reason (R): F is more electronegative than oxygen.**

- Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons.
- Fluorine (F) is indeed more electronegative than oxygen (O). The electronegativity values are approximately 4.0 for F and 3.5 for O on the Pauling scale.
- This means that F has a stronger pull on the electrons in a bond compared to O.
- Therefore, the reason that "F is more electronegative than oxygen" is **true**.

### Step 3: Analyze the Relationship Between A and R
- The assertion states that HF forms stronger hydrogen bonds than H2O, which we found to be false.
- The reason states that F is more electronegative than O, which is true. However, this does not directly support the assertion that HF forms stronger hydrogen bonds than H2O.
- Thus, while both statements are true, the reason does not correctly explain the assertion.

### Conclusion
- **Assertion (A)** is **false**.
- **Reason (R)** is **true**.
- Therefore, the correct answer is: **Assertion is false, but reason is true.**

### Final Answer
The answer is option 3: Assertion is false but reason is true.

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