Question

Pre-Lab Exercises Consider the following: A student added a solution of HCl to a solution containing Fe2+, Cr3+, K+, and Ag+ ions in a test tube. a) Which ion(s), if any, will likely precipitate out of solution? b) If precipitation occurred, what is (are) the formula(s) of the salt(s) that precipitate? c) What would happen to any precipitate formed in part (b) if aqueous ammonia is added to it? Write the equation for the reaction.

Answer 1

A. Ag⁺ ion (silver) ,will likely precipitate out of the solution as the solubility of silver chloride in acidic solution is 0.002 g/L which indicates the silver chloride is insoluble in acidic water in room temperature.

B.The formula of silver chloride as precipitate is AgCl. a strong covalent bond present in between silver and chlorine ion.

Ag⁺ + HCl $\rightarrow$ AgCl (solid) +H⁺

C. The precipitate( AgCl) will dissolve in ammonia solution. Silver ion form complex with ammonia and chlorine ion forms ionic bond with silver ion.

AgCl +NH₃$\rightarrow$(Ag(NH₃)₂)²⁺ +2Cl^-

so on addition of ammonia silver chloride dissolve in water.