Why water expands on changing its state to solid?

when we change state of a substance from liquid or gas to solid, it generally shrinks. But water expands on freezing i. e. changing its state to solid. Why? Are there such more substances?



  1. 0 Votes
    Actually this is pretty hard for you since u r only in 9th. But simply is- the structure of water is H-O-H. The H atom atom in water is partially positively charged and O atom is also partially negatively charged. So the H atom of one molecule attracts O atom of another molecule thus forming a cage like structure as shown- H O...H O H O..H...O H here you can see cage like structures. In these structures the air gets trapped and thus expands the area of ice formed. But remember it is a 3D structure. All the substances consisting of only H and O atoms expand while freezing. For more information, you can refer to 11th chemistry cbse text book. Chapter- Chemical Bonding and Structures.
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