Correct order of boiling order is :
`{:(CH_3CH_2-I,CH_3CH_2-Br,CH_3CH_2-Cl,CH_3-CH_2-F),(I,II,III,IV):}`

Options

A. `IVgtIIIgtIIgtI`
B. `IIgtIIIgtIVgtI`
C. `IgtIIgtIIIgtIV`
D. `IVgtIIIgtIgtII`

Explanation

To determine the correct order of boiling points for the given alkyl halides (CH₃CH₂-I, CH₃CH₂-Br, CH₃CH₂-Cl, CH₃-CH₂-F), we can follow these steps:

### Step 1: Identify the Compounds
The compounds given are:
1. CH₃CH₂-I (Iodoethane)
2. CH₃CH₂-Br (Bromoethane)
3. CH₃CH₂-Cl (Chloroethane)
4. CH₃CH₂-F (Fluoroethane)

### Step 2: Understand the Factors Influencing Boiling Point
The boiling point of a compound is influenced by:
- Molecular weight: Generally, higher molecular weight leads to higher boiling points.
- Type of halogen: Different halogens have different molecular weights and polarities, affecting boiling points.

### Step 3: Compare the Molecular Weights of Halogens
The halogens in the compounds have the following approximate molecular weights:
- Fluorine (F): ~19 g/mol
- Chlorine (Cl): ~35.5 g/mol
- Bromine (Br): ~80 g/mol
- Iodine (I): ~127 g/mol

### Step 4: Analyze the Compounds
Since all the alkyl groups (CH₃CH₂-) are the same, we only need to consider the halogen attached to each compound:
- CH₃CH₂-I has the heaviest halogen (Iodine), thus it will have the highest boiling point.
- CH₃CH₂-Br has Bromine, which is lighter than Iodine but heavier than Chlorine and Fluorine.
- CH₃CH₂-Cl has Chlorine, which is lighter than Bromine.
- CH₃CH₂-F has the lightest halogen (Fluorine), thus it will have the lowest boiling point.

### Step 5: Determine the Order of Boiling Points
Based on the molecular weights of the halogens, we can order the boiling points from highest to lowest:
1. CH₃CH₂-I (Iodoethane) - Highest boiling point
2. CH₃CH₂-Br (Bromoethane)
3. CH₃CH₂-Cl (Chloroethane)
4. CH₃CH₂-F (Fluoroethane) - Lowest boiling point

### Final Answer
The correct order of boiling points is:
**I > II > III > IV** (where I = CH₃CH₂-I, II = CH₃CH₂-Br, III = CH₃CH₂-Cl, IV = CH₃CH₂-F)