Chem qualitative analysis

• testing for carbonate ions = add dilute nitric acid --> effervescence
• testing for sulfate ions = add barium chloride --> white ppt of barium sulphate
• testing for chloride ions = add nitric acid and silver nitrate --> white ppt
• testing for iodide ions = add nitric acid & silver nitrate --> yellow ppt
• testing for bromide ions = add nitric acid & silver nitrate --> cream ppt
• testing for ammonium ions = add sodium hydroxide (aq) and heat --> turns red litmus paper blue
• colour of (Cu(H2O)6)2+ (aq) = blue
• Adding small amounts of NH3 to Cu2+: colour of Cu(OH)2 (s) --> blue ppt
• adding excess NH3 to Cu2+: [Cu(NH3)4(H2O)2)]2+(aq) --> dark blue
• adding excess HCl to [Cu(H2O)6]2+ --> [CuCl4]-2(aq) = yellow
• testing for alkenes = decolourises Bromine water
• test for haloalkane = add silver nitrate & ethanol & warm --> chloroalkae = white ppt, bromoalkane = cream ppt, iodoalkane = yellow ppt
• test for carbonyl = add 2,4-DNP --> orange ppt
• test for aldehyde = add tollens reagent --> silver mirror = redox reaction
• what does K2Cr2O7/H+ test for? primary & secondary alcohol + aldehyde - goes from orange to green
• test for carboxylic acid = add sodium carbonate --> bubbles
• colour of Cr in Cr2O72- = 6+ = orange
• colour of Cr in Cr3+ oxidation state = green
• adding NH3 drop wise to Cr3+ --> Cr(OH)3(s) = dark green ppt
• oxidation of Cr3+ with hot alkaline H2O2 --> CrO42-(aq) = yellow
• colour of a [Cr(HN3)6]3+ solution = purple