In Ice (solid water), the oxygen atom of each H₂O molecule is surrounded by 4 hydrogen atoms
Two hydrogen atoms attached by covalent and remaining Two hydrogen atoms attached by inter molecular hydrogen bonding.
Hydron bond In Water Molecule:
Due to hydrogen bonding in ice ,water molecules are arranged in the form of cage in which water molecules are tetrahedrally attached to four other water molecules.
Each oxygen atom forms four bonds out of which two are normal covalent bonds and two are hydrogen bonds.
Why ice Float in water ?
Hydrogen bond is longer than the normal covalent bond; thus, there are a large number of vacant spaces. Due to this open cage-like structure, volume becomes more and density becomes less. and hence water float in water.
Why water has maximum density at 4°c ?
When ice is heated From 0°c to 4°c, the number of hydrogen bonds are broken and water molecules come close to each other to fill up the vacant space.
There will be the contraction of volume as well as expansion, due to temperature rise but the effect of contraction is dominant over the effect of expansion from 0°c to 4°c.
Hence the resulting volume decreases and density increases and becomes maximum at 4°c.
Water density beyond 4°c :
When H₂O is further heated beyond 4°c the effect of expansion is dominant over the effect of contractions and density decreases beyond 4°c.
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