Hydrogen Bonding

Hydrogen as a Hydride

Hydrogen exists as a hydride in ionic salts.

The most abundant form of hydrogen is **protium**.

Dihydrogen ( ) can reduce some metal ions in aqueous solutions and oxides of metals (less active than iron) into their corresponding metals.

For example:

Additionally, dihydrogen can react with metal oxides:

Step 1: Understanding Intramolecular Hydrogen Bonding

Intramolecular hydrogen bonding occurs when a hydrogen bond forms between a hydrogen atom and an electronegative atom (such as oxygen or nitrogen) within the same molecule, rather than between different molecules.

Step 2: Examining the Given Options

Option (1): The molecule (hydroxy-nitrobenzene) contains a hydroxy (-OH) group, which can form an intramolecular hydrogen bond with the nitro (-NO₂) group. This leads to a stable structure with intramolecular hydrogen bonding.

Option (4) and Option (2): These molecules do not exhibit a favorable geometry for intramolecular hydrogen bonding due to their structure. Instead, they are more likely to engage in intermolecular hydrogen bonding.

Option (3): In HF, hydrogen bonding occurs, but it is intermolecular, not intramolecular.

Step 3: Conclusion

Thus, the correct answer is: Option (1)