Explain, why `o`-hydroxybenzaldehyde is a liquid at room temperature while `p`-hydroxybenzaldehyde is a high melting solid?

Explanation

In o-hydroxybenzalde , there is intrmolecular hydrogen bonding which further prevents association
of the molecular . In p-hydroxy benzaldehyde, there is intermolecular hydrogen bonding and hence , there
is association among the moleculas .

As a result , o-hydroxybenzaldehyde is a liquid whereas p-hydroxybenzaldehyde is a solid .
Similarly, in case of nitrophenol , we have
.