What is the correct order of the boiling points of \(\mathrm{H}_2 \mathrm{O}, \mathrm{HF}, \text{ and} \ \mathrm{NH}_3\) ?

1. HF > H₂O > NH₃

2. H₂O > HF > NH₃

3. NH₃ > HF > H₂O

4. NH₃ > H₂O > HF

Which of the following compounds shows the strongest hydrogen bonding?

1. HCl

2. H₂O

3. HI

4. H₂S