Hydrogen bonds are formed in many compounds e.g. `H_(2)O`, HF, `NH_(3)`. The boiling point of such compounds depends to a extent on the strength of hydrogen bond and the number of hydrogen bonds. The correct decreasing order of the boiling points above compounds is

Options

A. `HF gt H_(2) O gt NH_(3)`
B. `H_(2) O gt HF gt NH_(3)`
C. `NH_(3) gt HF gt H_(2)O`
D. `NH_(3) gt H_(2)O gt HF`

Explanation

To determine the correct decreasing order of the boiling points of the compounds H₂O, HF, and NH₃ based on the strength and number of hydrogen bonds, we can follow these steps:

### Step 1: Understand Hydrogen Bonding
Hydrogen bonding occurs when a hydrogen atom covalently bonded to a highly electronegative atom (like N, O, or F) interacts with another electronegative atom. The strength of hydrogen bonds varies depending on the electronegativity of the atoms involved and the number of hydrogen bonds that can form.

### Step 2: Analyze Each Compound
1. **HF (Hydrogen Fluoride)**:
- HF has a very strong hydrogen bond due to the high electronegativity of fluorine. Each HF molecule can form hydrogen bonds with multiple other HF molecules, leading to a high boiling point.

2. **H₂O (Water)**:
- Water has strong hydrogen bonds as well, primarily because of the two hydrogen atoms bonded to oxygen, allowing each water molecule to form up to four hydrogen bonds (two as a donor and two as an acceptor). This results in a relatively high boiling point.

3. **NH₃ (Ammonia)**:
- Ammonia can form hydrogen bonds due to the presence of nitrogen, but it has only one hydrogen atom bonded to nitrogen that can participate in hydrogen bonding with other ammonia molecules. Thus, the overall strength and number of hydrogen bonds are less than in HF and H₂O.

### Step 3: Compare Boiling Points
- **HF** has the highest boiling point due to the strong hydrogen bonds and the ability to form multiple bonds.
- **H₂O** follows, as it has strong hydrogen bonds and can form a significant number of them.
- **NH₃** has the lowest boiling point among the three, as it forms fewer and weaker hydrogen bonds compared to HF and H₂O.

### Conclusion
Based on the analysis of hydrogen bonding strength and the number of hydrogen bonds formed, the correct decreasing order of boiling points for the compounds is:
**HF > H₂O > NH₃**