The general formula of an ester where R represents an alkyl group is:

Options

A. ROH
B. RCOOH
C. RCOOR
D. RH

Answer

To determine the general formula of an ester where R represents an alkyl group, we can follow these steps:

### Step 1: Understand the Structure of an Ester
An ester is formed from the reaction between an alcohol and a carboxylic acid. The functional group of an ester is characterized by the presence of a carbonyl group (C=O) adjacent to an ether-like oxygen (–O–).

### Step 2: Write the General Structure
The general structure of an ester can be represented as:
\[ RCOOR' \]
Where:
- \( R \) is the alkyl group from the alcohol.
- \( R' \) is the alkyl group from the carboxylic acid.
- The carbonyl group (C=O) is connected to the oxygen atom (–O–).

### Step 3: Identify the General Formula
The general formula for an ester can be simplified to:
\[ C_nH_{2n}O_2 \]
This formula indicates that for every n carbon atoms in the alkyl groups, there are \( 2n \) hydrogen atoms and 2 oxygen atoms.

### Step 4: Conclusion
Thus, the general formula of an ester where R represents an alkyl group is:
\[ RCOOR' \]
or in terms of carbon and hydrogen:
\[ C_nH_{2n}O_2 \]

### Final Answer
The general formula of an ester is \( RCOOR' \).

---