Question

Which is more volatile: orthonitrophenol or paranitrophenol and why?

Answer 1

ortho nitro phenol is more volatile that para nitro phenol. There are two reasons:
1) Due to symmetric nature of para form, the intermolecular packing is higher for para nitro phenol
2) The inter molecular H bonding is present in para form, whereas there is intramolecular H bond in ortho form
That is why, the boiling point of ortho nitro phenol is lower that the para form and is hence more VOLATILE!!!