Qualitative Analysis Flashcards
What are the observations and the precipitate when NaOH and aqueous ammonia is added to a solution containing Ca²⁺ ions?
White ppt of Ca(OH)₂ with NaOH, insoluble in excess
No ppt with aqueous ammonia
What are the observations and the precipitate when NaOH and aqueous ammonia is added to a solution containing Zn²⁺ ions?
White ppt of Zn(OH)₂ soluble in excess NaOH and aqueous ammonia
What are the observations and the precipitate when NaOH and aqueous ammonia is added to a solution containing Pb²⁺ ions?
White ppt of Pb(OH)₂ insoluble in excess aqueous ammonia, soluble in excess NaOH to give colourless solution
(pure)
What are the observations and the precipitate when NaOH and aqueous ammonia is added to a solution containing Al³⁺ ions?
white ppt of Al(OH)₃ insoluble in aqueous ammonia, soluble in excess NaOH to give a colourless solution
What are the observations and the precipitate when NaOH and aqueous ammonia is added to a solution containing Cu²⁺ ions?
light blue ppt of Cu(OH)₂ formed in both cases, insoluble in excess NaOH, soluble in excess aqueous ammonia to give a deep blue solution
What are the observations and the precipitate when NaOH and aqueous ammonia is added separately to a solution containing Fe²⁺ ions and another containing Fe³⁺ ions?
Fe²⁺: Green ppt of Fe(OH)₂ , insoluble in excess NaOH and aqueous ammonia
Fe³⁺: Reddish Brown ppt of Fe(OH)₃ , insoluble in excess NaOH and aqueous ammonia
What are the observations when NaOH is added to a solution containing NH₄⁺ ions and warmed?
Colourless gas that turns damp red litmus paper blue (ammonia) is evolved
What is the test and observations for Hydrogen Gas?
Use a lighted splint, extinguishes with a pop sound
What is the test and observations for Oxygen Gas?
Use a glowing splint, relights
What is the test and observations for Carbon Dioxide Gas?
Bubble through Calcium Hydroxide solution (Limewater), a white precipitate (Calcium Carbonate) is formed
What is the test and observations for Chlorine Gas?
Use a piece of damp blue litmus paper. It turns red (HCl) before bleaching.
What is the test and observations for Sulfur Dioxide?
Use a filter paper dipped in acidified Potassium manganate (VII), turns from purple to colourless
What is the test and observations for Ammonia gas?
Use a piece of damp red litmus paper. It turns Blue.
(pure)
What are the tests and observations for Water Vapour?
Anhydrous Copper(II) Sulfate turns from white to blue. Or: Dry Cobalt (II) Chloride paper turns from blue to pink
What is the test and observations for the Nitrate Ion?
Add aqueous NaOH and a piece of Al foil, heat. Gas evolved turns red litmus blue (Ammonia).
What is the test and observations for the Carbonate Ion?
Add any dilute acid. Effervescence of Colourless Gas is observed. Gas forms a white ppt (Calcium Carbonate) with Calcium Hydroxide solution (Limewater)
What is the test and observations for the Chloride Ion?
Add dilute nitric acid, and then aqueous silver nitrate. White ppt of Silver Chloride is formed.
(pure)
What is the test and observations for the Iodide Ion?
Add dilute nitric acid, and then aqueous lead nitrate. A yellow ppt of Lead Iodide is formed
What is the test and observations for the Sulfate Ion?
Add dilute nitric acid, and then aqueous Barium nitrate. A white ppt of Barium Sulfate is formed.
(pure)
How does one distinguish between a solution containing Al³⁺ and Pb²⁺ ions since they both give the same observations with NaOH and aqueous ammonia?
Add aqueous potassium iodide KI. A yellow ppt of PbI₂ is formed with lead but no ppt is formed with Al³⁺
