Ncert Exercises & Solutions

Match the following parameters with a description for spontaneity.

\(\Delta\) (Parameters) \(\Delta r\ H^⊝\) \(\Delta r\ S^⊝\)\(\Delta r\ G^⊝\)	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.