Question

What does the electrolysis of a concentrated solution of potassium acetate give?
\[{\text{A}}{\text{.}}\] Methane
\[{\text{B}}{\text{.}}\] Ethane
\[{\text{C}}{\text{.}}\] Ethene
\[{\text{D}}{\text{.}}\] Ethyne

Answer 1

Hint: Here, we will proceed by giving a basic overview of the process of electrolysis of any concentrated solution. Then, we will write down the chemical reactions occurring at anode and cathode.

Complete answer:
The chemical formula of potassium acetate is \[{\text{C}}{{\text{H}}_3}{\text{COOK}}\]. Electrolysis basically refers to providing an aqueous solution or medium (i.e., electrolysis of a concentrated solution refers to mixing that concentrated solution with water i.e., aqueous medium). When a concentrated solution of potassium acetate undergoes electrolysis it forms ions (one positively charged ion and the other negatively charged ion).
The chemical reaction corresponding to the electrolysis of a concentrated solution of potassium acetate is shown under.
\[{\text{C}}{{\text{H}}_3}{\text{COOK}}\left( {{\text{aq}}} \right) \to {\text{C}}{{\text{H}}_3}{\text{CO}}{{\text{O}}^ - } + {{\text{K}}^ + }\]
At anode, \[{\text{C}}{{\text{H}}_3}{\text{CO}}{{\text{O}}^ - }\] ion loses electrons in order to form methane radial and carbon dioxide. Two methane radials join together to form a covalent bond between two methane radials. This results in the formation of ethane. The corresponding chemical reaction is shown under.
\[{\text{2C}}{{\text{H}}_3}{\text{CO}}{{\text{O}}^ - } \to 2\mathop {{\text{C}}{{\text{H}}_3}{\text{COO}}}\limits^. + 2{e^ - } \to 2\mathop {{\text{C}}{{\text{H}}_3}}\limits^. + 2{\text{C}}{{\text{O}}_2} + 2{e^ - } \to {\text{C}}{{\text{H}}_3} - {\text{C}}{{\text{H}}_3} + 2{\text{C}}{{\text{O}}_2} + 2{e^ - }\]
In the above chemical reaction occurring at anode, \[{\text{C}}{{\text{H}}_3} - {\text{C}}{{\text{H}}_3}\] can be written as \[{{\text{C}}_2}{{\text{H}}_6}\] where \[{{\text{C}}_2}{{\text{H}}_6}\] is ethane.
At cathode, reduction will occur.
Since, the reduction potential of \[{{\text{K}}^ + }\] ion is less than that of water (\[{{\text{H}}_2}{\text{O}}\]) and hence, the reduction of water molecule (\[{{\text{H}}_2}{\text{O}}\]) will occur by gaining two electrons released at anode (where oxidation occurs). This will result in the formation of hydrogen gas. The chemical reaction corresponding to this is written below.
\[{\text{2}}{{\text{H}}_2}{\text{O}} + 2{e^ - } \to 2{\text{O}}{{\text{H}}^ - } + {{\text{H}}_2}\left( {\text{g}} \right) \uparrow \]
Therefore, the electrolysis of a concentrated solution of potassium acetate gives 1 mole of ethane, 2 moles of carbon dioxide and 1 mole of hydrogen gas.

Hence, option B is correct.

Note: Electrolysis is one of the important processes in which electric current is passed through a substance in order to have a chemical change. Chemical change is simply referred to as either oxidation or reduction where oxidation results in loss of electrons and reduction results in the gaining of electrons.