The boiling point of hydride group members usually increases down the group due to increasing van der Waals forces. However, $H_{2}O$ is an anomaly.

• Oxygen is highly electronegative and small in size, allowing it to form strong Intermolecular Hydrogen Bonds.
• Each water molecule can form up to 4 hydrogen bonds, creating an extensive network.
• $H_{2}S,H_{2}Se,H_{2}Te$ cannot form effective hydrogen bonds as $S,Se,Te$ are larger and less electronegative.
• Consequently, $H_{2}O$ has a much higher boiling point ($100^{\circ }C$) than its congeners.