Question

Which of the following sodium salts of carboxylic acid is used for the preparation of n-hexane by Kolbe's electrolytic method?

• A. CHCH\(_2\)] COONa
• B. CH\(_3\)] COONa
• C. HCOONa
• D. CH\(_3\)] CH\(_2\)] CH\(_2\)] COONa
• E. CH\(_3\)] CH\(_2\)] CH\(_2\)] COONa

Hint:

In Kolbe's method, the sodium salt of a carboxylic acid undergoes electrolysis to form alkyl radicals that combine to give alkanes. For n-hexane, butyrate ion is used.

Answer 1

Answer: (E)

The Kolbe's electrolytic method is a method used to prepare alkanes by the electrolysis of sodium salts of carboxylic acids. In this process, the carboxylate ions from the salt undergo decarboxylation to form alkyl radicals, which combine to form the alkane.
- Option (A): CHCH\(_2\)] COONa (sodium propionate) would not give n-hexane.
- Option (B): CH\(_3\)] COONa (sodium acetate) is not used to prepare n-hexane.
- Option (C): HCOONa (sodium formate) is not used to prepare n-hexane.
- Option (D): CH\(_3\)] CH\(_2\)] CH\(_2\)] COONa (sodium butyrate) would lead to n-pentane, not n-hexane.
- Option (E): CH\(_3\)] CH\(_2\)] CH\(_2\)] COONa (sodium butyrate) is used to prepare n-hexane in Kolbe's electrolytic method by the decarboxylation of the butyrate salt.
Thus, the correct answer is (E) CH\(_3\)] CH\(_2\)] CH\(_2\)] COONa