Question

One mole of which of the following has the highest entropy?
(A) Liquid nitrogen
(B) Hydrogen gas
(C) Mercury
(D) Diamond

Answer 1

Hint:We have to find the molecule with the highest entropy. We know that entropy is a measurement of disorder in a system. There is an order followed by entropy in the three states of matter, with the help of that, the molecule can be determined.

Complete step by step solution:
> First, let us know about entropy. Entropy is defined on the basis of thermodynamics, and statistics.
> In terms of thermodynamics, it is used to determine the behaviour in terms of temperature, pressure of a system; whereas statistical definition tells us that it is used to measure the molecular disorder in a system.
> Thus, the greater disorder, and the system having high temperature will lead to the increase in entropy.
- The order followed is gas > liquid > solids
So, if we look at the given options, the diamond exists in the solid state, and is an allotrope of carbon.
> Now, the next if we consider mercury, and liquid nitrogen; we know that these both molecules exist in the liquid state.
Talking about hydrogen gas, it exists in the gaseous state.
We can also measure the entropy in consideration with the molar mass. It means the substance with the less molar mass will have higher entropy.
Thus, in the last we can conclude that the one molecule of hydrogen gas has the highest entropy.
Hence, the correct option is (B).

Note: Don’t get confused while determining the molecule with the higher entropy. If you don’t remember the order followed by the entropy in states of matter, just identify the gaseous molecule with the lower molecular mass.