Question

The least random state of the water system is
A. Ice
B. Liquid water
C. Steam
D. Randomness is the same in all

Answer 1

Hint: The second law of thermodynamics states that the entropy of the universe which includes the system and surrounding increases for an irreversible process.
It remains constant for a reversible process.
A system with a considerable degree of randomness possesses more entropy.

Complete step-by-step answer: Entropy is depicted as the estimation of the extent of disorderness in a state. It implies the anomaly or lack of uniformness in a thermodynamic system. It is denoted by ‘S’. It is an extensive property as the estimation of entropy or entropy change relies on the amount of matter comprising a thermodynamic system.
It is a state function as its value does not bank on the path by which the system acquired a particular state. It banks on only the initial and final state of the system.
A. Ice
This is the solid state of the water system.
It has a regular or ordered crystalline structure. There is no free space.
The constituent particles are tightly packed thus maintaining a uniform order.
There is no anomaly in the structure of the solid.
So, the degree of randomness is very low.
Hence, A is correct.
B. Liquid water
It is a polar inorganic compound.
It has no taste, odour or colour and exists as a liquid at room temperature.
Its structure is not closely packed as solid.
The constituent particles are close to each other. These particles slide over each other and thus liquid water can flow.
Thus, the degree of randomness in liquid water is more than in solid.
So, B is incorrect.
C. Steam
Water in the gaseous phase is called steam.
In a gaseous state, the size of the constituent particles is negligible as compared to the volume of the container in which the gas is present.
There is enough free space in this state.
So, these particles move haphazardly and are far apart from each other.
The degree of randomness is greatest in the gaseous state.
So, C is incorrect.
D. Randomness is the same in all
Randomness depends on the structure of the state.
Each state has a different structure. So, randomness can not be the same in all the states.
So, D is incorrect.

So, option A is correct.

Note: Degree of randomness relies on the structure of the particular state of water.
Ice, liquid water and steam are solid, liquid and gaseous states of the water system. Steam has the highest degree of randomness as the constituent particles move randomly due to its small size and free space available for movement. Ice has the least degree of randomness due to its closely packed structure.