. At its melting point, ice is lighter than water because
(a) molecules are more closely packed in solid state
(b) ice crystals have hollow hexagonal arrangement of molecules
(c) on melting of ice the molecules shrinks in size
(d) ice forms mostly heavy water on first melting.
Correct Option is (b)
Ice is lighter than water at its melting point because ice crystals have a hollow hexagonal arrangement of H 2 O molecules.
When ice first melts,it is largely heavy water. In the hexagonal honeycomb structure of ice, each H 2 O molecule is surrounded by three H 2 O molecules.