For a given reaction, `Delta H = 35.5 kJ mol^(-1)` and `Delta S = 83.6 JK^(-1) mol(-1)`. The reaction is spontaneous at : (Assume that `Delta H and Delta S` do not vary with temperature)

Options

A. `T lt 425` K
B. `T gt 425`K
C. All temperatures
D. `T gt 298`K

Answer

B

Explanation

`Delta G= Delta H- T Delta S lt 0`
`Delta H lt T Delta S`
`T gt (Delta H)/(Delta S)= (35.5 xx 1000)/(83.6) = 425K`
Since `Delta H and Delta S` are positive so reaction will be spontaneous at `T gt 425K`