Which of the following is false about molar entropy?

Options

A. it is same for all type of gases
B. For the gas of comparable mass. It decreases with the increases in atomicity
C. Under identical condition, it is greater for heavier gas.
D. For ideal gas of comparable molar mass it decreases with the increase in thermo molecular attractions.

Answer

To determine which statements about molar entropy are false, let's analyze each option step by step.

### Step 1: Analyze the first option
**Statement**: "It is the same for all types of gases."
- **Analysis**: This statement is false. Molar entropy varies with the type of gas due to differences in molecular structure, atomicity, and other factors. Different gases have different molar entropies.

### Step 2: Analyze the second option
**Statement**: "For a gas of comparable mass, it increases with the increase in atomicity."
- **Analysis**: This statement is also false. While it is true that molar entropy tends to increase with atomicity, the phrase "comparable mass" can be misleading. Molar entropy is influenced by both the mass and the complexity of the gas molecules. Thus, this statement does not hold true universally.

### Step 3: Analyze the third option
**Statement**: "In identical conditions, it is greater for a heavier gas."
- **Analysis**: This statement is true. Under the same conditions of temperature and pressure, heavier gases typically have higher molar entropies due to their greater number of accessible microstates.

### Step 4: Analyze the fourth option
**Statement**: "For an ideal gas of comparable molar mass, it decreases with the increase in thermo-molecular interactions."
- **Analysis**: This statement is false. Increased thermo-molecular interactions generally lead to a decrease in the number of accessible microstates, which would decrease entropy. However, the relationship is not straightforward and depends on the specific conditions and types of interactions.

### Conclusion
From the analysis above, the false statements about molar entropy are:
1. It is the same for all types of gases.
2. For a gas of comparable mass, it increases with the increase in atomicity.
4. For an ideal gas of comparable molar mass, it decreases with the increase in thermo-molecular interactions.

### Final Answer
The false statements are options 1, 2, and 4.

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