A chemical process involves decrease in enthalpy and decrease in entropy. If the magnitude of change in enthalpy is 1000 times the change in entropy, the process is spontaneous at

$\begin{array}{c}\mathrm{Given} \mathrm{\Delta H}=-\mathrm{Ve}\mathrm{and}\mathrm{\Delta s}=-\mathrm{Ve};\\ \mathrm{\Delta G}=\mathrm{\Delta H}-\mathrm{T}∆\mathrm{S}\end{array}$

At equilibrium, $\mathrm{\Delta G}=0$

$\begin{array}{l}\therefore {\mathrm{T}}_{\mathrm{eq}}=\frac{\mathrm{\Delta H}}{\mathrm{\Delta S}}\\ {\mathrm{T}}_{\mathrm{eq}}=\frac{1000}{1}\\ {\mathrm{T}}_{\mathrm{eq}}=1000\mathrm{K}\\ {\mathrm{T}}_{\mathrm{eq}}={727}^{\mathrm{o}}\mathrm{C}\\ \mathrm{\Delta G}=\mathrm{\Delta H}-\mathrm{T\Delta S}\\ \mathrm{\Delta G}=-\mathrm{Ve}-\mathrm{T}\left(-\mathrm{Ve}\right)\end{array}$

Process becomes spontaneous when $\mathrm{\Delta G}=-\mathrm{Ve}$ which is only possible when temperature is below 1000K (or) 727°c.