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In solid ammonia, each NH(3) molecule ha...

In solid ammonia, each `NH_(3)` molecule has six other `NH_(3)` molecules as nearest neighbours. `DeltaH` sublimation of `NH_(3)` at the melting point is `30.8 k J mol^(-1)`, and the estimated `DeltaH` sublimation in the absence of hydrogen bonding is `14.4 kJ mol^(-1)`. the strength of a hydrogen bond is `NH_(3)` is

A

`5.47 kJ " mol"^(-1)`

B

`10.93 kJ " mol"^(-1)`

C

`16.40 kJ " mol"^(-1)`

D

`-16.4 kJ " mol"^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
A
Total strength of all H-bonds `=30.8-14.4=16.4`
kJ `mol^(-1)` There are six nearest neighbours but each H-bond involves two molecules. Hence the effective neighbours `=3`
`:.` Strength of H-bond `=(16.4)/3`
`=5.47 kJ "mol"^(-1)`
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