When electricity is passed through an aqueous solution of brine, it decomposes to form 'X'. This process is called 'Y' because of the products formed. Products 'Z' and 'W' are formed at the cathode and the anode respectively. Identify, X, Y, Z and W.

When electricity is passed through an aqueous solution of brine, it decomposes to form 'X'. This process is called 'Y' because of the products formed. The products that are formed as 'Z' and 'W' are formed at the cathode and the anode respectively. X - Sodium hydroxide, Y- Chlor-alkali, Z - Hydrogen W - Chlorine respectively.
Because sodium hydroxide (caustic soda, an alkali) and chlorine are created during the electrolysis of $\mathit{NaCl}$ solution, the process is known as the chlor-alkali process (brine solution). $\mathit{NaOH}$ and $H_2$ are the cathode products, whereas chlorine is the anode product.
Anode reaction:

 $2C{l}^{-}\to C{l}_2+2e^{-}$
Cathode reaction:

 $N{a}^{+}+H_{2}O+e^{-}\to \mathit{NaOH}+\frac{1}{2}{H}_2$
Overall reaction:

 $2\mathit{NaCl}+2H_{2}O\to 2\mathit{NaOH}+H_2+C{l}_2$