Vapour pressure of pure ` CS _ 2 ` and ` CH _ 3 COCH _ 3 ` are 512 mm of Hg and 312 mm of Hg respectively. Total vapour pressure of mixture is 600 mm of Hg then find incorrect statement :

Options

A.
B. Does not obey Raoult's law
C. Endothermic solution
D. after adding 100 ml of each, then net volume is less then 200 ml

Answer

To solve the problem, we need to analyze the given data regarding the vapor pressures of pure substances and the vapor pressure of their mixture.

### Given Data:
- Vapor pressure of pure CS2 (carbon disulfide) = 512 mm Hg
- Vapor pressure of pure CH3COCH3 (acetone) = 312 mm Hg
- Total vapor pressure of the mixture = 600 mm Hg

### Step 1: Understanding Raoult's Law
According to Raoult's Law, the total vapor pressure of a mixture of two volatile liquids is the sum of the partial pressures of each component. The partial pressure of each component in the mixture can be calculated using the formula:
\[ P_{total} = P_{A} + P_{B} \]
Where:
- \( P_{A} \) is the partial pressure of component A (CS2)
- \( P_{B} \) is the partial pressure of component B (acetone)

### Step 2: Calculating the Expected Total Vapor Pressure
If we assume that the mixture behaves ideally, we can calculate the expected total vapor pressure using the mole fractions of each component. However, since we are given the total vapor pressure (600 mm Hg), we can analyze the deviation from ideal behavior.

### Step 3: Identifying the Type of Deviation
The total vapor pressure of the mixture (600 mm Hg) is greater than the vapor pressure of both pure components. This indicates that the mixture exhibits positive deviation from Raoult's Law. In positive deviation:
- The interactions between different molecules (A and B) are weaker than the interactions between like molecules (A-A and B-B).
- This results in a higher vapor pressure than expected.

### Step 4: Evaluating the Statements
Now, we need to evaluate the statements provided in the question to find the incorrect one.

1. **Statement A**: The attraction or interaction between AA and BB is more compared to AB.
- This statement is correct as it describes positive deviation.

2. **Statement B**: The mixture does not obey Raoult's Law.
- This statement is also correct because the mixture shows positive deviation.

3. **Statement C**: It is an endothermic solution.
- This statement is correct as positive deviation typically involves endothermic mixing.

4. **Statement D**: After adding 100 ml of each, the net volume is less than 200 ml.
- This statement is incorrect because in the case of positive deviation, the volume of the mixture is expected to be greater than the sum of the individual volumes.

### Conclusion
The incorrect statement is **Statement D**.