For the formation of Cr ₂ O ₃ and Al ₂ O ₃ , values of _f G^ are 540 ~kJ ~mol ⁻¹ and -827 ~kJ ~mol ⁻¹ respectively. What will be the possibility for reaction of Cr ₂ O ₃ by Al ?

Step-by-step solution

aligned & 2 Cr + 3 2 O ₂ Cr ₂ O ₃ ; _f G ^ =-540 ~kJ ~mol ⁻¹ & 2 Al + 3 2 O ₂ Al ₂ O ₃ ; _f G ^ =-827 ~kJ ~mol ⁻¹ aligned Substrating equation (i) from (ii) gathered 2 Al + Cr ₂ O ₃ Al ₂ O ₃+2 Cr _r G=[-827-(-540)] kJ mol ⁻¹=-287 ~kJ ~mol ⁻¹ gathered because for the reduction by A l , value of G^ is negative, therefore reaction is feasible.