Answer: d) ΔS is positive and ΔH is negative
Explanation:
According to Gibb's equation:
[tex]\Delta G=\Delta H-T\Delta S[/tex]
[tex]\Delta G[/tex] = Gibbs free energy
[tex]\Delta H[/tex] = enthalpy change
[tex]\Delta S[/tex] = entropy change
T = temperature in Kelvin
[tex]\Delta G[/tex]= +ve, reaction is non spontaneous
[tex]\Delta G[/tex]= -ve, reaction is spontaneous
[tex]\Delta G[/tex]= 0, reaction is in equilibrium
a) ΔS is negative and ΔH is positive
[tex]\Delta G=(-ve)-T(+ve)[/tex]
[tex]\Delta G=(-ve)(-ve)=-ve[/tex]
Reaction is spontaneous at all temperatures.
b) ΔS is positive and ΔH is positive
[tex]\Delta G=(+ve)-T(+ve)[/tex]
[tex]\Delta G=(+ve)(-ve)=-ve[/tex]
Reaction is spontaneous at high temperatures.
c) ΔS is negative and ΔH is negative
[tex]\Delta G=(-ve)-T(-ve)[/tex]
[tex]\Delta G=(-ve)(+ve)=-ve[/tex]
Reaction is spontaneous at low temperatures.
d) ΔS is positive and ΔH is negative
[tex]\Delta G=(+ve)-T(-ve)[/tex]
[tex]\Delta G=(+ve)(+ve)=+ve[/tex]
Reaction is non spontaneous or thermodynamically unfavored at all temperatures.
