In the qualitative cation analysis for 1.00 mL of the saturated PbCl 2 ( a q ) at 25 ∘ C , the presence of sufficient Pb 2+ to produce a precipitate of PbCrO 4 (s) needs to be shown. Concept introduction: When a solution is treated with HCl and a precipitate is formed, one or more of these cations may be present in the solution; Pb 2+ , Hg 2 2+ , Ag + . To identify these individual cations, the precipitate is filtered and the dried precipitate is further subjected to testing. PbCl 2 is more soluble than other two precipitates; Hg 2 Cl 2 and AgCl. When the temperature increases, solubility of a solid increases. So, when the precipitate obtained from group 1 analysis is washed with hot water, PbCl 2 precipitate dissolves in hot water and only Hg 2 Cl 2 and AgCl remains as precipitates. Presence of Pb 2+ can be identified by adding a CrO 4 2- solution. When Pb 2+ reacts with CrO 4 2- , it forms a yellow color precipitate PbCrO 4 .
In the qualitative cation analysis for 1.00 mL of the saturated PbCl 2 ( a q ) at 25 ∘ C , the presence of sufficient Pb 2+ to produce a precipitate of PbCrO 4 (s) needs to be shown. Concept introduction: When a solution is treated with HCl and a precipitate is formed, one or more of these cations may be present in the solution; Pb 2+ , Hg 2 2+ , Ag + . To identify these individual cations, the precipitate is filtered and the dried precipitate is further subjected to testing. PbCl 2 is more soluble than other two precipitates; Hg 2 Cl 2 and AgCl. When the temperature increases, solubility of a solid increases. So, when the precipitate obtained from group 1 analysis is washed with hot water, PbCl 2 precipitate dissolves in hot water and only Hg 2 Cl 2 and AgCl remains as precipitates. Presence of Pb 2+ can be identified by adding a CrO 4 2- solution. When Pb 2+ reacts with CrO 4 2- , it forms a yellow color precipitate PbCrO 4 .
Solution Summary: The author analyzes the presence of Pb 2+ in a saturated solution of HCl, and explains how it is more soluble than other two precipitates.
In the qualitative cation analysis for 1.00 mL of the saturated PbCl2(aq) at 25∘C, the presence of sufficient Pb2+to produce a precipitate of PbCrO4(s) needs to be shown.
Concept introduction:
When a solution is treated with HCl and a precipitate is formed, one or more of these cations may be present in the solution; Pb2+, Hg22+, Ag+. To identify these individual cations, the precipitate is filtered and the dried precipitate is further subjected to testing.
PbCl2 is more soluble than other two precipitates; Hg2Cl2 and AgCl. When the temperature increases, solubility of a solid increases. So, when the precipitate obtained from group 1 analysis is washed with hot water, PbCl2 precipitate dissolves in hot water and only Hg2Cl2 and AgCl remains as precipitates. Presence of Pb2+ can be identified by adding a CrO42- solution. When Pb2+ reacts with CrO42-, it forms a yellow color precipitate PbCrO4.
You had prepared 100.0 mL of Buffer C, in which you mixed 1.35 g of sodium benzoate, C7H5O2 with 10.00 mL of 1.0 M benzoic acid.
What would be the initial pH of Buffer C?
Explain why 6M NH3 and not 6M NaOH solution is used when separation Fe3+ and Al3+ ions from Ca2+, Cu2+, and K+ ions in the qualitative analysis of cations. Write appropriate chemical equations to support your conclusion.
1. Explain why 6M NH3 and not 6M NaOH solution is used when separation Fe3+ and Al3+ ions from Ca2+, Cu2+, and K+ ions in the qualitative analysis of cations. Write appropriate chemical equations to support your conclusion.
2.
Consider the reaction:
Fe (s) + Cu2+ (aq) ⇌ Fe2+ (aq) + Cu (s)
If [Cu2+] = 0.50 M, what [Fe2+] is needed to increase Ecell by 0.10 V above E0cell at 20 °C?