Q.Show hydrogen bonding in the above molecule with the help of a diagram.

Step 1. In a single H$_2$O molecule oxygen is far more electronegative than hydrogen, so each O-H bond is strongly polarised: the hydrogens carry a partial positive charge ($\delta^+$) and the oxygen a partial negative charge ($\delta^-$), concentrated on its two lone pairs.

Step 2. A hydrogen bond forms when a $\delta^+$ hydrogen of one water molecule lines up with a $\delta^-$ lone pair on the oxygen of a NEIGHBOURING molecule -- drawn as a dotted line (the solid lines are the covalent O-H bonds):

Drawing the diagram the question asks for: mark delta-plus on each O-H hydrogen and delta-minus on each oxygen, then connect the H of one molecule to an oxygen lone pair of th …

• Describing hydrogen bonding as if it were a normal covalent bond of comparable strength; it is a considerably weaker, purely electrostatic intera …