The value of`Delta _(f) f^(Ө)` for formation of `Cr_(2) O_(3)` is – 540 kJmol−1and that of `Al_(2) O_(3)` is `– 827 kJmol^(−1)`. Is the reduction of `Cr_(2) O_(3)` possible with Al ?

The value of`Delta _(f) f^(Ө)` for formation of `Cr_(2) O_(3)` is –

1.	The value of`Delta _(f) f^(Ө)` for formation of `Cr_(2) O_(3)` is – 540 kJmol−1and that of `Al_(2) O_(3)` is `– 827 kJmol^(−1)`. Is the reduction of `Cr_(2) O_(3)` possible with Al ?
Answer» chemical equaltion for the foramtion of `Cr_(3)O_(3)` and `Al_(2)O_(3)` are as follows (a) `(4)/(3) Cr(s) +(3)/(2)O_(2)(g) to (2)/(3) Cr_(2) O_(3) (s) :` `DeltaG_(f)^(@)` =- 540kj mol^(-1)` `(b) (4)/(3) Al (s) +(3)/(2) O_(2) (g) to (2)/(3) Al_(2)O_(3) (s) :` ` Delta G_(f)^@)=- 827 Kj mol^(-1)` Substring equcation (a) from equaction (b) ,we get `(4/93)Al(s) +(2)/(3) Cr_(2)O_(3) (s) to` `(2)/(3) Al_(2)O_(3) (s) +(4)/(3)Cr(s) DeltaG_(f)^(@)=- 287 kjmol^(-1)` As can be seen `Delta _(r)G^(@)` is nagative , thius , reducation of `Cr_(2)O_(3)` Al is possible.