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Given that the food energies of :N-=N i...

Given that the food energies of `:N-=N` is 946kJ `"mol"^(-1)` , H-H is 435 kJ `"mol"^(-1),N-N` is 159 kJ `"mol"^(-1)`, and N-H is 389 kJ `"mol"^(-1)` , the heat of formation of hydrazine in the phase in kJ `"mol"^(-1)` is :

A

833

B

101

C

334

D

1268

Text Solution

Verified by Experts

The correct Answer is:
B
`N_(2)+2H_(2)rarr1N_(2)H_(4)" " , DeltaH_(f)`
`DeltaH_(f)=1xxE_(N-=N)+2E_(H-H)-4E_(N-H)-1E_(N-N)`
`=[(1xx946)+(2xx435)-4xx(389)-1xx(159)]kJ`
`=101 kJ//"mol"`
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