The product, which is not obtained during the electrolysis of brine solution is

We need to identify the product that is NOT obtained during the electrolysis of brine solution (concentrated aqueous NaCl).

When brine is electrolyzed, water at the cathode is reduced instead of Na+ because its reduction potential is lower, following the reaction $$ 2\text{H}_2\text{O} + 2e^- \to \text{H}_2(g) + 2\text{OH}^- $$. This yields hydrogen gas (H₂).

At the anode, chloride ions undergo oxidation according to $$ 2\text{Cl}^- \to \text{Cl}_2(g) + 2e^- $$, producing chlorine gas (Cl₂).

The hydroxide ions generated at the cathode then combine with sodium ions in the solution to form sodium hydroxide (NaOH).

Considering the options, Option A (H₂) is indeed produced at the cathode, Option B (HCl) does not form during brine electrolysis, Option C (NaOH) is formed in solution, and Option D (Cl₂) is produced at the anode.

Thus HCl is not a product of brine electrolysis, making the correct answer Option B: HCl.