The pair likely to form the strongest hydrogen bonding is

The compound/s which will show significant intermolecular $H$-bonding is/are :
$(a)$ $o$-Nitrophenol
$(b)$ $N$-($4$-hydroxyphenyl)acetamide
$(c)$ $2,6$-di-tert-butylphenol

Define hydrogen bond. Is it weaker or stronger than the van der Waals forces?

The correct order of boiling point in the following compounds is

Viscosity of a liquid arises due to strong intermolecular forces existing between the molecules. Stronger the intermolecular forces,greater is the viscosity. Name the intermolecular forces existing in the following liquids and arrange them in the increasing order of their viscosities. Also give reason for the assigned order in one line.
Water,hexane $(CH_3CH_2CH_2CH_2CH_2CH_3)$,glycerine $(CH_2OHCH(OH)CH_2OH)$

Select the incorrect match.