Why is ortho nitrophenol steam volatile?

This takes me back to organic chemistry class! Ortho nitrophenol is steam volatile because of intramolecular hydrogen bonding. In the ortho isomer, the nitro group (-NO2) and hydroxyl group (-OH) are close enough to form hydrogen bonds within the same molecule. This reduces intermolecular hydrogen bonding between different molecules, which means the compound has lower boiling point and can vaporize more easily with steam. The meta and para isomers can't form these internal bonds, so they form stronger bonds between molecules and have higher boiling points.