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

Options

A. The reaction of 0.624 mol ofAI
B. The formation of 0.624 mol of `Al _(2) O _(3)`
C. The reaction of 0.312 mol of Al
D. The formation of 0.150 mol of`Al _(2) O _(3)`

Explanation

`Al + (3)/(2) O _(2) to (1)/(2) Al _(2) O _(3)`,
`overset(27 g) (Delta H) =- 837.8 kJ overset(51 g) (mol ^(-1))`
`Delta H =- 837. 8 kJ mol ^(-1)`
(A) `0. 624` mol of `Al = 837.8 xx 0. 6 24` on combustion gave `= 523 kJ.` Hence , false
(B)Formation of `0. 624` mol of `Al _(2) O _(3)` gave `= 837.8 xx 2 xx 0. 624 = 1045 kJ.` Hence, false,
(C ) `0. 312` mol of Al on combustion gave `= 261 kJ.` Hence, false
(D) Formation of `0. 150` mol of `Al _(2) O _(3)` gave `= 251. 3 kJ . `Hence, true.