Which of the following statement is incorrect :-

Options

A. Boiling point of alkylhalide is `R-IgtR-BrgtR-ClgtR-F`
B. Alkyl halide are soluble in organic solvent and insoluble in water generally
C. Freons are used for aerosol propellant, refrigeration and air conditioning purpose.
D. `-o and -m` dichlorobenzene has higher melting point than those of `p-isomer`

Answer

To determine which of the following statements is incorrect, we will analyze each statement one by one.

### Step 1: Analyze the First Statement
**Statement 1:** The boiling point of alkyl halides is in the order of increasing size of the halogen.

- **Explanation:** The boiling point of alkyl halides is influenced by the size of the halogen atom. Larger halogens (like iodine) have stronger van der Waals forces due to their larger electron cloud, leading to higher boiling points. Therefore, the order of boiling points for alkyl halides is: I > Br > Cl > F. This statement is **correct**.

### Step 2: Analyze the Second Statement
**Statement 2:** Alkyl halides are soluble in organic solvents and insoluble in water.

- **Explanation:** Alkyl halides are generally non-polar or weakly polar, making them more soluble in organic solvents (which are also non-polar) than in water (which is polar). This statement is **correct**.

### Step 3: Analyze the Third Statement
**Statement 3:** Freons are used in aerosol propellant, refrigeration, and air conditioning purposes.

- **Explanation:** Freons, which are a class of chlorofluorocarbons (CFCs), are indeed used in refrigeration and air conditioning systems due to their ability to evaporate easily and absorb heat. This statement is **correct**.

### Step 4: Analyze the Fourth Statement
**Statement 4:** Ortho and meta dichlorobenzene have higher melting points than those of para isomers.

- **Explanation:** The melting points of isomers can be influenced by their molecular symmetry and packing efficiency. Para isomers tend to have better packing efficiency due to their symmetrical structure, leading to higher melting points compared to ortho and meta isomers. Therefore, this statement is **incorrect**.

### Conclusion
After analyzing all four statements, we find that **the fourth statement is incorrect**.

### Final Answer
The incorrect statement is: **Ortho and meta dichlorobenzene have higher melting points than those of para isomers.**

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