Textbook Problem

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Without looking up their standard entropies in reference tables, identify which of the following lists the materials in order of increasing entropy.

1. (a) H₂O(ℓ) < NaCl(s) < NH₃(g)
2. (b) H₂O(ℓ) < NH₃(g) < NaCl(s)
3. (c) NaCl(s) < H₂O(ℓ) < NH₃(g)
4. (d) NH₃(g) < H₂O(ℓ) < NaCl(s)

Interpretation Introduction

Interpretation: the order of standard entropies in the given lists of materials is to be identified from the given options.

Concept introduction:

In Spontaneous process, energy transfer from higher concentration to lower, or the energy is dispersed.

Entropy (S) is the quantity to measure the dispersal of energy in the spontaneous processes.

The order of degrees of freedom in solid, liquid and gaseous state molecules are,

$solid<liquid<gas$

The entropy of a system is directly proportional to its degrees of freedom.

Explanation of Solution

Reason for correct answer:

In the given lists,

The three molecules are in different states, such as solid, liquid and gas.

The order of degrees of freedom in solid, liquid and gaseous state molecules are,

$solid<liquid<gas$

The entropy of a system is directly proportional to its degrees of freedom.

Therefore,

The increasing order of entropy in the given lists is,

$NaCl(s)<H_{2}O(l)<N{H}_3(g)$

Hence, the correct option is c