The standard heat of combustion of `Al` is `-837.8 kJ mol^(-1)` at `25^(@)C`. If `Al` reacts with `O_(2)` at `25^(@)C`, which of the following release `250kJ` of heat?

Options

A. The reaction of `0.624 mol of AI`
B. The formation fo `0.624 mol of AI_(2)O_(3)`
C. The reaction of `0.312 mol of AI`
D. The formation of `0.150 mol of AI_(2)O_(3)`

Explanation

`underset(27g)AI +(3)/(2)O_(2) rarr (1)/(2)underset(51g)AI_(2)O_(3)`
`DeltaH = -837.8 kJ mol^(-1)`
a. `0.624 mol of AI = 837.8 xx 0.624` on combustion gave `= 523 kJ`.
Hence false.
b. Formation of `0.624 mol of AI_(2)O_(3)` gave
`= 837.9 xx2xx0.624`
`=1045 kJ`
Hence, false.
c. `0.312 mol of AI` on combustion gave `= 261 kJ`. Hence, false.
d. Formation of `0.150 mol of AI_(2)O_(3) gave = 251.3 kJ`. Hence, ture.