Question

Pre-Lab for Qualitative Analysis of Silver Group I Cations Lab 1. What are the ions that are considered Group I cations? 2. Based on the Activities Series of Elements, explain why Group I ions would form precipitates when a strong, concentrated acid (such as HCI) is added to them. 3. Pby, and K Cro, will react with each other to form a precipitate if the concentrations are high enough. Write the complete, balanced equation for the reaction of Pbs and K.CrO460) (Including state of matter.) 4. Ag and HCl will react with each other to form a precipitate if the concentrations are high enough Write the complete, balanced equation for the reaction of Ags and HCl (Including state of matter.) 5. An unknown sample was qualitatively analyzed. It formed a white precipitate upon the addition of 2M HCI. The white precipitate was dissolved in 6M ammonia. No precipitate was formed. Potassium chromate was added to the solution. The result was a yellow precipitate. What Group ion(s) is/are present in the unknown sample?

Answer 1

Group first cations are Ag^+ , Pb^+2 , Hg^+1 .

These forms solid precipitates of Chloride as AgCl , PbCl2 and Hg2Cl2 respectively with HCl solution and consider as group first cations .