Question

Hydrogen bonds are formed in many compounds, e.g., ` H_(2) O, HF, NH_(3) ` . The boiling point of such compounds depends to a large extent on the strength of hydrogen bond and the number of hydrogen bonds. The correct decreasing order of the boiling points of above compounds is :
A. `HF gt H_(2)O gt NH_(3)`
B. `H_(2)O gt HF gt NH_(3)`
C. `NH_(3) gt HF gt H_(2)O`
D. `NH_(3)gt H_(2) O gt HF`

Answer 1

Correct Answer - B
Strength of H-bond is in the order : `H………..Fgt H……….Ogt H………N.`
But each `H_(2)O ` molecule is linked to 4 other `H_(2)O ` molecules through H-bonds whereas each HF molecule
is linked only to two HF molecular . Hence .b.pt .of `H_(2)O gt b.pt of HF`