Question

to test tube A and B contain solution of sodium Bromide or potassium Bromide and sodium iodide and potassium iodide how would you find which tube contain which salt

Answer 1

When chlorine (as a gas or dissolved in water) is added to sodium bromide solution, the chlorine takes the place of the bromine. Because chlorine is more reactive than bromine, it displaces bromine from sodium bromide.  The solution turns brown. This brown colour is the displaced bromine. The chlorine has gone to form sodium chloride.  In this equation, the Cl and Br have swapped places:  chlorine + sodium bromide → sodium chloride + bromine  Cl2(aq) + 2NaBr(aq) → 2NaCl(aq) + Br2(aq)  This type of reaction happens with all the halogens. A more reactive halogen displaces a less reactive halogen from a solution of one of its salts

Answer 2

Answer:

Add few drops of silver nitrate solution to test tube A and B.

(i) KBr solution will react with silver nitrate to form a creamy pale yellow precipitate of silver bromide which are partially soluble in ammonia solution.

KBr + AgNO3 → KNO3 + AgBr↓

(ii) KI solution will react with silver nitrate to form a yellow precipitate of silver iodide which does not dissolve in concentrated ammonia solution.

KI + AgNO3 → KNO3 + AgI↓