Ncert Exercises & Solutions

Match the following parameters with a description for spontaneity.

	\(\Delta r\ H^⊝\)	\(\Delta r\ S^⊝\)	\(\Delta r\ G^⊝\)		Description
A.	+	–	+	1.	Non-spontaneous at high temperature
B.	–	–	+ at high T	2.	Spontaneous at all temperatures
C.	–	+	–	3.	Non-spontaneous at all temperatures

Codes:

Hint: For a spontaneous reaction,

∆ G

value is less than zero.

A. When

∆_{r} G^{⊝}

is positive, the reaction is non-spontaneous at all temperatures

B. When

∆_{r} G^{⊝}

is positive at high temperature means the reaction is non-spontaneous at high temperature.

C. When

∆_{r} H^{⊝}

= negative means it favours,

∆_{r} S^{⊝}

= positive means it also favours.

∆_{r} G^{⊝}

= negative means reaction is spontaneous at all temperatures.