Home
Class 12
CHEMISTRY
The correct thermodnamic conditions for ...

The correct thermodnamic conditions for the spontaneous reaction at all temperature is:

A

`DeltaH gt 0 and DeltaS lt 0`

B

`DeltaH lt 0 and DeltaS gt 0`

C

`DeltaH lt 0 and DeltaS lt 0`

D

`DeltaH lt 0 and DeltaS = 0`

Text Solution

Verified by Experts

The correct Answer is:
B, D
We have the Gibbs Helmholtz reaction for spontaneity as
`DeltaG=DeltaH-TDeltaS`
For reaction to be spontaneous , `DeltaG` must be negative . For this , `DeltaH` should be negative and `DeltaS` should be positive.
`therefore DeltaH lt 0 and DeltaS gt 0`
and also `DeltaS=0` shows `DeltaG` a negative quantity.
Promotional Banner

Similar Questions

Explore conceptually related problems

State the thermodynamic conditions for spontaneous occurrence of a process.

What are spontaneous processes ? Mention the conditions for a reaction to be spontaneous at constant temperature and pressure.

In isolated system, find the condition for spontaneous reaction:

The signs of DeltaH,DeltaS and DeltaG for a non-spontaneous reaction at all temperature would e

For an endothermic reaction to be spontaneous

Predict whether a spontaneous reaction will occur:

In which case, process will be spontaneous at all temperature?

In which case, process will be spontaneous at all temperature?

What is the sign of DeltaS for a spontaneous reaction ?

Free enegry , G = H - TS , is state function that indicates whther a reaction is spontaneous or non-spontaneous. If you think of TS as the part of the system's enegry that is disordered already, then (H -TS) is the part of the system's energy that is still ordered and therefore free to cause spontaneous change by becoming disordered. Also, DeltaG = DeltaH - T DeltaS From the second law of thermodynamics, a reaction is spontaneous if Delta_("total")S is positive, non-spontaneous if Delta_("total")S is negative, and at equilibrium if Delta_('total")S is zero. Since, -T DeltaS = DeltaG and since DeltaG and DeltaS have opposite sings, we can restate the thermodynamic criterion for the spontaneity of a reaction carried out a constant temperature and pressure. IF DeltaG lt 0 , the reaction is spontaneous. If DeltaG gt 0 , the reaction is non-spontaneous. If DeltaG = 0 , the reaction is at equilibrium. Read the above paragraph carefully and answer the following questions based on the above comprehension. For the spontaneity of a reaction, which statement is true?