Question

What do you observe when Cl₂ is passed through potassium iodide (KI) solution.

Answer 1

If in the solution of KI (Potassium iodide), we pass Chlorine gas (Cl₂), then Chlorine will displace iodine from KI, and form Potassium Chloride (KCl), and liberates iodine, 

 \[\ce{Cl2  (aq) + 2 KI(aq)  → 2 KCl (aq) + I2 (aq)}\]

 When Iodine gas is passed into starch solution the solution becomes blue-black in colour.