Question

Four half-reactions, I to IV are shown below:

1. \[\ce{2Cl^- -> Cl2 + 2e^-}\]
2. \[\ce{4OH^- -> O2 + 2H2O + 2e^-}\]
3. \[\ce{Na^+ + e^- -> Na}\]
4. \[\ce{2H^+ + 2e^- -> H2}\]

Which two of these reactions are most likely to occur when concentrated brine is electrolysed?

विकल्प

• I and III

• II and III

• I and IV

• II and IV

Answer 1

I and III

Explanation:

When concentrated brine (sodium chloride solution) is electrolysed, the following two half-reactions are most likely to happen:

\[\ce{2Cl^- -> Cl2 + 2e^-}\]

Chloride ions (Cl⁻) lose electrons to generate chlorine gas (Cl₂) in this process, which takes place at the anode.

\[\ce{Na^+ + e^- -> Na}\]

Sodium ion (Na⁺) gains electrons during this process at the cathode, forming sodium (Na).