Arrange the following compounds in decreasing order of their boiling points
(i) `CH_(3)Cl`
(ii) `CH_(3)CH_(2)Cl`
(iii) `CH_(3)CH_(2)CH_(2)Cl`
(iv) `CH_(3)CH_(2)CH_(2)CH_(2)Cl`

Options

A. `(iii) gt(iv) gt (i) gt (ii)`
B. `(iv) gt (iii) gt (ii) gt (i)`
C. `(i) gt (iii) gt (ii) gt (iv)`
D. `(i) gt (ii) gt (iii) gt (iv)`

Answer

To arrange the compounds in decreasing order of their boiling points, we will analyze the molecular structure and the number of carbon atoms in each compound. The compounds given are:

1. \( CH_3Cl \) (Chloromethane)
2. \( CH_3CH_2Cl \) (Chloroethane)
3. \( CH_3CH_2CH_2Cl \) (Chloropropane)
4. \( CH_3CH_2CH_2CH_2Cl \) (Chlorobutane)

### Step 1: Identify the number of carbon atoms in each compound
- \( CH_3Cl \): 1 carbon atom
- \( CH_3CH_2Cl \): 2 carbon atoms
- \( CH_3CH_2CH_2Cl \): 3 carbon atoms
- \( CH_3CH_2CH_2CH_2Cl \): 4 carbon atoms

### Step 2: Understand the relationship between molar mass and boiling point
The boiling point of a compound is generally influenced by its molar mass. As the number of carbon atoms increases, the molar mass of the compound also increases. Higher molar mass typically leads to a higher boiling point due to increased van der Waals forces.

### Step 3: Arrange the compounds based on the number of carbon atoms
Since the boiling point increases with the number of carbon atoms, we can arrange the compounds in the following order based on the number of carbon atoms:

- \( CH_3CH_2CH_2CH_2CH_2Cl \) (4 carbon atoms) - Highest boiling point
- \( CH_3CH_2CH_2Cl \) (3 carbon atoms)
- \( CH_3CH_2Cl \) (2 carbon atoms)
- \( CH_3Cl \) (1 carbon atom) - Lowest boiling point

### Final Order of Boiling Points
Thus, the compounds arranged in decreasing order of their boiling points are:
1. \( CH_3CH_2CH_2CH_2Cl \) (Chlorobutane)
2. \( CH_3CH_2CH_2Cl \) (Chloropropane)
3. \( CH_3CH_2Cl \) (Chloroethane)
4. \( CH_3Cl \) (Chloromethane)

### Answer
The correct order of boiling points is:
\[ CH_3CH_2CH_2CH_2Cl > CH_3CH_2CH_2Cl > CH_3CH_2Cl > CH_3Cl \]

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