Decreasing order of boiling point of I to IV follow
`{:("Methylformate","Ethylformate","Iso-propylformate","n-Propylformate"),(I,II,III,IV):}`

Options

A. `IgtIIgtIIIgtIV`
B. `IIIgtIVgtIIgtI`
C. `IVgtIIIgtIIgtI`
D. `IgtIIgtIVgtIII`

Explanation

To determine the decreasing order of boiling points for the compounds: Methylformate (I), Ethylformate (II), Isopropylformate (III), and n-Propylformate (IV), we can follow these steps:

### Step 1: Understand the Structures
- **Methylformate (I)**: Contains one methyl group (CH3).
- **Ethylformate (II)**: Contains one ethyl group (C2H5).
- **Isopropylformate (III)**: Contains a branched isopropyl group (C3H7).
- **n-Propylformate (IV)**: Contains a straight-chain propyl group (C3H7).

### Step 2: Analyze Molecular Weights
- Methylformate has the lowest molecular weight due to having the smallest alkyl group.
- Ethylformate has a higher molecular weight than methylformate.
- Isopropylformate and n-Propylformate have similar molecular weights, but the structure differs (branched vs. straight chain).

### Step 3: Determine the Effect of Molecular Weight on Boiling Point
- Generally, the boiling point increases with increasing molecular weight due to stronger van der Waals forces.
- Methylformate (I) will have the lowest boiling point due to the lowest molecular weight.
- Ethylformate (II) will have a higher boiling point than methylformate due to its higher molecular weight.

### Step 4: Compare Isopropylformate and n-Propylformate
- Between Isopropylformate (III) and n-Propylformate (IV), the straight-chain n-Propylformate (IV) will have a higher boiling point than the branched Isopropylformate (III) because straight-chain molecules have stronger intermolecular forces compared to branched ones.

### Step 5: Arrange in Decreasing Order
Based on the analysis:
1. **n-Propylformate (IV)** - Highest boiling point
2. **Isopropylformate (III)**
3. **Ethylformate (II)**
4. **Methylformate (I)** - Lowest boiling point

### Final Order
The decreasing order of boiling points is:
**IV > III > II > I**