Question

The concentrated aqueous solution of potassium salts of acetic acid and propanoic acid are electrolysed. Which of the following hydrocarbon(s) is/are produced?

• A. $CH_{3}CH_{3}$ only
• B. $CH_{3}CH_{2}CH_{3}$ only
• C. $CH_{3}CH_{3}$ and $CH_{3}CH_{2}CH_{2}CH_{3}$
• D. $CH_{3}CH_{2}CH_{2}CH_{3}$ and $CH_{3}CH_{2}CH_{3}$

Answer 1

Answer: (C)

When concentrated aqueous solution of potassium salts of acetic acid and propanoic acid are electrolysed. $CH_{3}CH_{3}$ and $CH_{3}CH_{2}CH_{2}CH_{3}$ are produced as follows

$CH_{3}COOK\left(\right.aq\left.\right) \rightarrow CH_{3}COO^{-}\left(\right.aq\left.\right)+K^{+}\left(\right.aq\left.\right)$

$CH_{3}CH_{2}COOK\left(\right.aq\left.\right) \rightarrow CH_{3}CH_{2}COO^{-}\left(\right.aq\left.\right)+K^{+}\left(\right.aq\left.\right)$

Anode: A. $2CH_{3}COO^{-}\left(\right.aq\left.\right) \rightarrow CH_{3}-CH_{3}+2CO_{2}+2e^{-}$

B. $2CH_{3}CH_{2}COO^{-}\left(\right.aq\left.\right) \rightarrow CH_{3}CH_{2}CH_{2}CH_{3}+2CO_{2}+2e^{-}$

Cathode: $2HOH+2e^{-} \rightarrow H_{2}\left(\right.g\left.\right)+2OH^{-}$