If n is the number of carbon atoms in the potassium salt of a carboxylic acid, then the alene formed on electrolysis of aqueous solution of a salt of a carboxylic acid containing n cabon atoms would have carbon atoms equal to

Options

A. n
B. n-1
C. 2n-1
D. 2(n-1)

Explanation

To solve the problem, we need to understand the process of electrolysis of a potassium salt of a carboxylic acid and how it relates to the number of carbon atoms in the resulting alkene.

### Step-by-Step Solution:

1. **Identify the Number of Carbon Atoms in the Salt**:
- Given that \( n \) is the number of carbon atoms in the potassium salt of a carboxylic acid, we can denote the carboxylic acid as having \( n \) carbon atoms.

2. **Understanding the Electrolysis Process**:
- During the electrolysis of the potassium salt of the carboxylic acid, the carboxylic acid is formed. This process typically involves the elimination of carbon atoms.

3. **Determine the Number of Carbon Atoms in the Resulting Alkene**:
- When the electrolysis occurs, it is known that two carbon atoms are eliminated from the carboxylic acid. Therefore, if we start with \( n \) carbon atoms in the carboxylic acid, we will have:
\[ \text{Remaining Carbon Atoms} = n - 2 \]

4. **Relate the Remaining Carbon Atoms to the Alkene**:
- The alkene formed will have the same number of carbon atoms as the remaining carboxylic acid after the elimination of two carbon atoms. Therefore, the number of carbon atoms in the alkene will be:
\[ \text{Carbon Atoms in Alkene} = n - 2 \]

5. **Final Calculation**:
- Since we are looking for the number of carbon atoms in the alkene formed, we conclude that the number of carbon atoms in the alkene is \( n - 2 \).

### Conclusion:
Thus, the number of carbon atoms in the alkene formed on electrolysis of the aqueous solution of a salt of a carboxylic acid containing \( n \) carbon atoms is \( n - 2 \).