Question

The unit of entropy is
A. $J{{K}^{-1}}mo{{l}^{-1}}$
B. $K{{J}^{-1}}mo{{l}^{-1}}$
C. $KJmo{{l}^{-1}}$
D. ${{J}^{-1}}{{K}^{-1}}mo{{l}^{-1}}$

Answer 1

Hint: Entropy is a kind of thermodynamic process. Thermodynamic process deals with the change of systems state from one state to another. There are four different types of thermodynamic processes known as: Isothermal, Adiabatic, Isobaric and Isochoric.

Complete answer:
The concept of entropy was given by German physicist Rudolf Clausius in 1850. Entropy is defined as the randomness or disorder of a system and it is used to describe the behavior of systems in terms of thermodynamic processes like temperature, pressure, heat capacity etc. There is another definition of entropy which describes it measures molecule disorder. Entropy is also measured as state function i.e. it depends on the state of the system only not on the path followed by it. Entropy is represented by S. It is an extensive property.
Entropy goes on increasing with the increase in disorder of an isolated system. If reactants break into more number of products during a chemical reaction then entropy also increases. Entropy also depends on temperature, at higher temperature it has greater randomness than a system which is at lower temperature. Order of entropy in case of solid, liquid and gas can be described as:
$gas > liquid > solid$
The S.I. unit of entropy is $J{{K}^{-1}}mo{{l}^{-1}}$and CGS unit is $cal{{K}^{-1}}mo{{l}^{-1}}$.

Hence we can say that option A is the correct answer.

Note:
Rather than entropy there is also another term entropy change which is defined as the amount of heat emitted or absorbed isothermally and reversibly divided by the absolute temperature. The equation for entropy change is given by $\Delta S={{q}_{rev,iso}}/T$.