Question

a reaction having a positive delta H and a positive delta S will:

always be spontaeous

always be non spontaneous

be spontaneous at low T

be spontaneous at high T

2. A reaction having a positive delta H and a negative delta S will:

always be spontaeous

always be non spontaneous

be spontaneous at low T

be spontaneous at high T

3. A reaction having a neg. delta H and a positive delta S will

always be spontaeous

always be non spontaneous

be spontaneous at low T

be spontaneous at high T

4. A reaction having neg. delta H and neg. delta S will:

always be spontaeous

always be non spontaneous

be spontaneous at low T

be spontaneous at high T

Answer 1

As, ∆G = ∆H - T∆S and reaction is spontaneous when ∆G is negative.

1) Answer is spontaneous at high T. Because at high temperature, T∆S dominate over ∆H and ∆G become negative.

2) Answer is always be non spontaneous. Because equation become ∆G = ∆H + T∆S. Hence ∆G is always positive and reaction is non-spontaneous.

3) Answer is always be spontaneous. Because equation become ∆G = -∆H - T∆S. Hence ∆G is always Negative and process is spontaneous.

4) Answer is spontaneous at low T. Because equation become ∆G = -∆H + T∆S thus at low T, ∆H dominate and ∆G become negative and reaction is spontaneous.