Salt Analysis
CHEMISTRY PRACTICAL NOTES - SALT ANALYSIS S.No. | EXPERIMENT | OBSERVATION | INFERENCE | 1(a) | Noted the colour of the salt | BluePale greenGreenPale pinkColourless | May be Cu2+May be Fe2+May be Ni2+, Cu2+May be Mn2+Absence of Cu2+, Fe2+, Ni2+, Cu2+, Mn2+ | (b) | Noted the physical state of the salt | (i)Amorphous(ii)crystalline | May be CO32-May be Cl-, Br-, SO42-, NO3- | 2 | Action of heat:The given salt is heated in a dry test tube. | (i)Reddish brown vapours(ii)Crackling sound(iii)Yellow when salt and white when cold(iv)Colourless gas giving pungent smelling gas(v) No characteristic change | Presence of NO3-, NO2-Presence of nitrates of lead and bariumPresence of Zn2+Presence of NH4+Absence of nitrate, nitrite, zinc and ammonium ions | 3 | Solubility: a) In water b) In dil. HCl | SolubleSoluble in dil. HCl but insoluble in water | Water soluble saltsPresence of CO32- | 4 | Flame test:A paste of the salt was made with few drops of con. HCl and was introduced into the non-luminous flame. | (i)Brick red colour is imparted to the flame(ii) Crimson red(iii) Apple green(iv) Bluish green(v)No characteristic colour is imparted to the flame | Presence of Ca2+Presence of Sr2+Presence of Ba2+Presence of Cu2+Absence of Ca2+, Sr2+, Ba2+, Cu2+ | 5 | Ash test:To the salt added cobalt nitrate solution and dilute nitric acid. A filter paper dipped in this mixture was burnt. | (i) Green ash(ii) Blue ash(iii) Pink ash 2Co(NO3)2 2 CoO + 4NO2 + O2 ZnO + CoO CoZnO2 MgO + CuO MgCoO2 Al2O3 + CoO Co(Al2O3)3(iv) No characteristic coloured ash | Presence of Zn2+Presence of Al3+Presence of Mg2+Absence of Zn2+, Al3+, Mg2+ | 6 | Dry tests for anion:To a pinch of the salt , dil HCl was added and heated. | (i)Brisk effervescence, colourless gas evolved turning lime water milkyCO32- + 2H+ CO2 + H2OCO2 + Ca(OH)2 CaCO3 + H2O(ii)Colourless gas with