During electrolysis of aqueous sodium chloride

A. Sodium metal is obtained at anode

B. Hydrogen is evolved at cathode

C. Oxygen is evolved at anode

D. Oxygen is evolved at cathode

E. Chlorine is evolved at anode

Choose the correct answer from the option given below.

B, E only

The correct answer is option 1. B, E only.

Let us break down the electrolysis of aqueous sodium chloride in detail:

The electrolysis of aqueous sodium chloride (NaCl) occurs in a cell with two electrodes (anode and cathode) submerged in an aqueous solution of sodium chloride. The electrodes are usually made of inert materials such as graphite or platinum.

1. Cathode Reaction (Reduction at the Cathode):
At the cathode (negative electrode), water (H₂O) is reduced:

\[ \text{2H}_2\text{O} + \text{2e}^- \rightarrow \text{H}_2(g) + \text{2OH}^- \]
This reaction results in the evolution of hydrogen gas (\(H_2\)) and the formation of hydroxide ions (\(OH^-\)) in the aqueous solution.
So, at the cathode, hydrogen gas is evolved.

2. Anode Reaction (Oxidation at the Anode):
At the anode (positive electrode), chloride ions (\(Cl^-\)) from the sodium chloride solution are oxidized:
\[ \text{2Cl}^-\text{(aq)} \rightarrow \text{Cl}_2(g) + \text{2e}^- \]
This reaction results in the evolution of chlorine gas (\(Cl_2\)) at the anode.
So, at the anode, chlorine gas is evolved.

3. Overall Reaction:
Combining the cathode and anode reactions, the overall reaction can be expressed as:
\[ \text{2H}_2\text{O} + \text{2Cl}^-\text{(aq)} \rightarrow \text{H}_2(g) + \text{Cl}_2(g) + \text{2OH}^- \]
The net result is the liberation of hydrogen gas and chlorine gas along with the formation of hydroxide ions.

In summary:
Cathode (Negative Electrode):  Hydrogen gas (\(H_2\)) is evolved.
Anode (Positive Electrode):  Chlorine gas (\(Cl_2\)) is evolved.

Therefore, the correct answer to the given options is (1) B, E only, indicating that hydrogen is evolved at the cathode (B) and chlorine is evolved at the anode (E).