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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

`-462KJ`

C

`-1365KJ`

D

`+2730KJ`

Text Solution

Verified by Experts

The correct Answer is:
B
`2Al+(3)/(2)O_(2)rarrAl_(2)O_(3),DeltaH=-1596KJ" "…(i)`
`2Cr+(3)/(2)O_(2)rarrCr_(2)O_(3),DeltaH=-1134KJ" " …(ii)`
By (i),, (ii)
`2Al+Cr_(2)O_(3)rarr2Cr+Al_(2)O_(3),DeltaH=-462KJ`
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