The values of Δ H and Δ S for a reaction are 30 kJ mol -1 and100 JK -1 mol -1 respectively. Then the temperature above which the reaction will become spontaneous is

Question

The values of Δ H and Δ S for a reaction are 30 kJ mol -1 and100 JK -1 mol -1 respectively. Then the temperature above which the reaction will become spontaneous is (A) 300 K (B) 30 K (C) 100 K (D)  300°C

Tardigrade Admin · Accepted Answer

∵ Δ G=Δ H-T.Δ S Δ G=30000-(T× 100) J mol-1 For spontaneous process Δ G should be negative, i.e., Δ G < 0 and this occurs when TΔ S>Δ H. T>(Δ H/Δ S) T>(30000/100) T>300 K

Q. The values of $Δ H$ and $Δ S$ for a reaction are $30 k J m o l^{- 1}$ and $100 J K^{- 1} m o l^{- 1}$ respectively. Then the temperature above which the reaction will become spontaneous is

$300 K$

$30 K$

$100 K$

$30 0^{\circ} C$

$∵$ $Δ G = Δ H - T .Δ S$
$Δ G = 30000 - (T \times 100) J m o l^{- 1}$
For spontaneous process $Δ G$ should be negative, i.e.,
$Δ G < 0$
and this occurs when
$T Δ S > Δ H .$
$T > \frac{Δ H}{Δ S}$
$T > \frac{30000}{100}$
$T > 300 K$

Q. The values of ΔH and ΔS for a reaction are 30kJmol−1 and100JK−1mol−1 respectively. Then the temperature above which the reaction will become spontaneous is

300K

30K

100K

300∘C