`H_(2)O` is liquid while `H_(2)S` is a gas, though oxygen and sulphur, both belong to the same group of the periodic table.

Explanation

Oxygen atom is smaller and more electronegative than sulphur. Hence in `H_(2)O` molecule, O atom forms strong intermolecular H-bonds. However, in `H_(2)S` molecule, S-atom, owing to its larger size and lesser electronegativity than O-atom, cannot form H-bonds. strong intermolecular H-bonds bind `H_(2)O` molecules in an associated state, while molecules of `H_(2)S` are held by weak van der waals forces. therefore `H_(2)O` is a liquid while `H_(2)S` is a gas at room temperature.