KCET2021Chemistryp Block Elements (Group 15, 16, 17 & 18)
The correct order of boiling point in the following compounds is
Options
- AHF > H ₂ O > NH ₃
- BH ₂ O > HF ²> NH ₃
- CNH ₃> H ₂ O > HF
- DNH ₃> HF > H ₂ O
Correct answer
B. H ₂ O > HF ²> NH ₃
Step-by-step solution
The correct order of boiling point of given hydrides is as follows H ₂ O > HF > NH ₃ Strength of H-bonding depends upon size and electronegativity of the atom. Smaller the size of the atom, greater is the electronegativity and stronger is the H -bonding. But each H ₂ O molecule has two hydrogen atom, whereas each HF molecule has only one hydrogen atom. Hydrogen bonding is more strong in H ₂ O molecules. While NH ₃ molecules due to less electronegativity of ' N ' atom than ' F^ atom is less polar and hence, have wea