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The enthalpies of formation of Al(2)O(3)...

The enthalpies of formation of `Al_(2)O_(3)` and `Cr_(2)O_(3)` are `-1596KJ` and `-1134KJ` respectively. `DeltaH` for the reaction
`2Al+Cr_(2)O_(2)rarr2Cr+Al_(2)O_(3)` is

A

`-2730kJ`

B

`-462lK`

C

`-1365kJ`

D

`+2730kJ`

Text Solution

Verified by Experts

The correct Answer is:
B
`2Al+3/2O_(2)toAl_(2)O_(3),DeltaH=-1596KJ`…….i
`2Cr+2/2O_(2)toCr_(2)O_(3), DeltaH=-1134kJ`…….ii
By i-ii
`2Al+Cr_(2)O_(3)to2Cr+Al_(2)O_(3), DeltaH=-462kJ`
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