Analyze Statement I

Statement I says: $o$-Nitrophenol is steam volatile due to intramolecular hydrogen bonding.

• In $o$-nitrophenol, the $-OH$ group and $-NO_2$ group are adjacent, so intramolecular hydrogen bonding occurs.
• Because of this, molecules of $o$-nitrophenol are less associated with each other.
• Lower intermolecular association means lower boiling tendency relative to the para isomer, so it becomes steam volatile.

Therefore, Statement I is true.

Analyze Statement II

Statement II says: $o$-Nitrophenol has high melting due to hydrogen bonding.

• High melting point generally results from strong intermolecular forces and better crystal packing.
• But in $o$-nitrophenol, hydrogen bonding is intramolecular, not intermolecular.
• Intramolecular hydrogen bonding actually reduces intermolecular attraction and gives poorer crystal association.
• Hence, $o$-nitrophenol does not have high melting point due to hydrogen bonding.
• In fact, $p$-nitrophenol has stronger intermolecular hydrogen bonding and therefore higher melting point.

Therefore, Statement II is false.

Choose the correct option

• Statement I: True
• Statement II: False

So the correct option is:

$\boxed{\text{B}}$

Comparison with stored answer

Stored correct answer = B

Our derived answer = B

Hence, they agree.