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).