In conversion of lime-stone to lime,
`CaCO_(3(s)) to CaO_((s)) + CO_(2(g))` the values of `DeltaH^@` and `DeltaS^@` are `+179.1 kJmol^(-1)` and `160.2 J//K` respectively at `298K` and 1 bar. Assuming that `DeltaH^@` and `DeltaS^@` do not change with temperature, temperature above which conversion of lime-stone to lime will be spontaneous is :

Options

A. `1118 K`
B. `1008 K`
C. `1200 K`
D. `845 K`

Answer

A

Explanation

`DeltaG^(@)=DeltaH^(@)-TDeltaS^(@)`
Since `DeltaH^(@)` is `+ve` and `TDeltaS` is also `+ve`, for `DeltaG^(@)` to be `-ve`
`TDeltaS^(@) gt DeltaH^(@)` i.e. `T gt(DeltaH^(@))/(DeltaS^(@))`
i.e. `(179100 J)/(160.2 JK^(-1)) gt 1118 K`