Which of the following statements are incorrect?

Options

A. Molar volume of every gas at `STP is 22.4 L`
B. compressibility factor of ideal gas is one
C. All gases will have equal value of average `KE` at a given temperature
D. At absolute zero, `KE` is `3//2 R`.

Answer

To determine which statements are incorrect, we will analyze each statement one by one based on our knowledge of the gaseous state.

### Step-by-Step Solution:

1. **Statement 1**: "Molar volume of every gas at STP is 22.4 liters."
- At Standard Temperature and Pressure (STP), one mole of any ideal gas occupies a volume of 22.4 liters. This is a well-established fact in chemistry.
- **Conclusion**: This statement is **correct**.

2. **Statement 2**: "Compressibility factor of ideal gas is one."
- The compressibility factor (Z) is defined as Z = PV/RT. For an ideal gas, the equation of state PV = nRT holds true, leading to Z = 1.
- **Conclusion**: This statement is **correct**.

3. **Statement 3**: "All gases will have equal value of average kinetic energy at a given temperature."
- The average kinetic energy of gas molecules is given by the formula \( KE = \frac{3}{2} k T \) for one molecule or \( KE = \frac{3}{2} R T \) for one mole. Since this formula depends only on the absolute temperature (T), all gases at the same temperature will indeed have the same average kinetic energy.
- **Conclusion**: This statement is **correct**.

4. **Statement 4**: "At absolute zero, kinetic energy is three by two R."
- At absolute zero (0 Kelvin), the temperature is zero, and since the average kinetic energy is directly proportional to the absolute temperature, the average kinetic energy will also be zero.
- **Conclusion**: This statement is **incorrect**.

### Final Answer:
The incorrect statement is **Statement 4**.