Q. What is the structure of $ {{H}_{2}}O $ ?
JIPMERJIPMER 2002
Solution:
The electron dot-structure of $ {{H}_{2}}O $ is $ \underset{(lps\,+\,\sigma \,-\,bps\,=\,2\,+\,2\,=\,4)}{\mathop{H--\underset{.\,\,.}{\overset{.\,\,.}{\mathop{O}}}\,--H}}\, $ Hence, oxygen atom undergoes $ s{{p}^{3}}\text{-} $ hybridisation. It should be tetrahedral, but due to presence of 2 lone-pairs of electron, it is angular with H?O?H, bond angle $ =104.5{}^\circ . $
