Question

The values of `DeltaH` and `DeltaS` for the reaction
`C("graphite")+CO_(2)(g)to2CO(g)` are `170 kJ` and `170 JK^(-1)` respectively. The reaction will be spontaneous at
A. `990 K`
B. `1140 K`
C. `1100 K`
D. `1110 K`

Answer 1

Correct Answer - A
`DeltaG=DeltaH-TDeltaS`
`DeltaH=170xx1000=170000J`
`:. DeltaG=DeltaH-TDeltaS`
For equilibrium
`DeltaG=0`
`:. 0=170000J-Txx170 J`
or `T=(170000)/(170)=1000K`
`T` should be less than `1000 K` for spontaneity.