# In the electrolysis of brine for the production of chlorine , the by products are

$(a)\;\text{Oxygen and$CO_2$} \\(b)\;\text{Oxygen and NaOH} \\(c)\; \text{ Oxygen and HCl.} \\ (d)\;\text{ hydrogen and oxygen.}$

Chlorine is the main product and it is formed at anode.
Hence b is the correct answer.