Directions: Each question contains Statement- 1 and Statement-2 and has the following choices (a), (b), (c) and (d), out of which ONLY ONE is correct. (a) Statement- 1 is True, Statement- 2 is True; Statement- 2 is a correct explanation for Statement- 1 (b) Statement- 1 is True, Statement- 2 is True; Statement- 2 is NOT a correct explanation for Statement-1 (c) Statement- 1 is True, Statement- 2 is False (d) Statement- 1 is False, Statement- 2 is True Statement 1 o-Nitrophenol is steam volatile whereas p-nitrophenol is not steam volatile. and Statement 2 There is intra molecular hydrogen bonding in o-nitrophenol, whereas there is intermolecular hydrogen bonding in p-nitrophenol.

Hydrogen bonding is a type of chemical bond that is highly relevant in multiple areas of chemistry, especially in explaining the properties of molecules like water and organic compounds. It occurs when a hydrogen atom attached to a strongly electronegative atom, like oxygen or nitrogen, experiences an attractive force with another electronegative atom in a nearby molecule or within the same molecule.

For instance, in organic chemistry, the functional groups containing oxygen - such as hydroxyl (-OH) - often participate in hydrogen bonding. This interaction isn't just a minor detail; it has a profound influence on physical properties like boiling point, solubility, and yes, steam volatility. Intramolecular hydrogen bonding, where the bond forms within the same molecule, can affect the molecule's shape and reactivity, while intermolecular hydrogen bonding, occurring between different molecules, leads to higher boiling points and, in certain conditions, lower volatility of substances.

In the context of organic compounds such as nitrophenol isomers, the position of functional groups (like the hydroxyl and nitro groups) determines whether hydrogen bonding is inter- or intramolecular, which in turn influences the compound's behavior when exposed to steam.

Steam volatility is an important characteristic relating directly to a substance's physical properties and its interaction with water vapor. Specifically, a compound's steam volatility determines its ability to vaporize or transition into a gas phase when it comes into contact with steam. This is particularly significant in organic chemistry and various separation processes where steam can be used to purify components based on their volatility.

Factors influencing steam volatility include molecular weight, intermolecular forces, and the presence of hydrogen bonding. Molecules held together by strong intermolecular forces, such as intermolecular hydrogen bonds, typically have lower steam volatility because they require more energy to overcome these attractions. In contrast, those with weaker or intramolecular hydrogen bonds, which do not significantly contribute to the aggregate intermolecular forces, demonstrate increased steam volatility.

Understanding this concept helps in grasping why certain isomers, despite having almost the same molecular formula, can behave so differently under the same conditions. For IIT JEE aspirants, mastering steam volatility can aid in tackling questions related to distillation and separation techniques used both in laboratory and industrial scales.

Nitrophenol isomers provide excellent insights into how slight changes in molecular structure can lead to significant differences in chemical properties. Isomers are compounds with the same molecular formula but different structures or spatial arrangements of atoms. The position of the nitro group (-NO2) and hydroxyl group (-OH) on the benzene ring of nitrophenol isomers, for instance, is crucial in determining their physical and chemical characteristics.

Ortho (o-) and para (p-) nitrophenol are the two isomers often discussed in the context of hydrogen bonding and steam volatility. In o-nitrophenol, intramolecular hydrogen bonding occurs because the hydroxyl and nitro groups are close enough to interact within the same molecule, making the compound more steam volatile. However, in p-nitrophenol, the hydroxyl and nitro groups are far apart, allowing for intermolecular hydrogen bonding which decreases steam volatility and increases the boiling point.

The learning curve for students involves understanding that isomers like o-nitrophenol and p-nitrophenol are great examples of how the arrangement of functional groups affects physical properties and reactivity—a concept crucial for problem-solving in organic chemistry sections of competitive exams like the IIT JEE.