Salt Analysis Chart PDF

SEMI – MICRO QUALITATIVE ANALYSIS OF SIMPLE INORGANIC SALT _______________________________________________________________ CATIONS: Pb2+ ,Hg2+ ,Cu2+ ,Cd2+ , Ag+ , Fe2+ , Fe3+ , Al3+ , Zn2+ , Mn2+ , Co2+ , Sr2+ , Ba2+ , Mg2+ , NH4+ ANIONS: CO32- , S2- , SO32- , SO42- , NO2- , NO3- , Cl- , Br2- , PO4...

SEMI – MICRO QUALITATIVE ANALYSIS OF SIMPLE INORGANIC SALT _______________________________________________________________ CATIONS: Pb2+ ,Hg2+ ,Cu2+ ,Cd2+ , Ag+ , Fe2+ , Fe3+ , Al3+ , Zn2+ , Mn2+ , Co2+ , Sr2+ , Ba2+ , Mg2+ , NH4+ ANIONS: CO32- , S2- , SO32- , SO42- , NO2- , NO3- , Cl- , Br2- , PO43- , CH3COO- _______________________________________________________________ PRELIMINARY TESTS 1. Note the state (amorphous or crystalline) and colour of salt. 2. Test the solubility of the salt in the following solutions: i. Water (cold and hot) ii. Dilute HCl (cold and hot) iii. Dilute HNO3 (cold and hot) _______________________________________________________________ IDENTIFICATION OF ACID RADICALS (ANIONS) This part is the classified into three groups: FIRST GROUP OF ACID RADICALS The acid radicals involved in this group are carbonate(CO32-), Sulphide(S2-), Sulphite(SO32-), Thiosulphate(S2O32-) and nitrate(NO2-). The group reagent is dilute hydrochloric acid. EXPERIMENT OBSERVATION INFERENCE Salt + dil. HCl Effervescence or evolution of gases 1st group of acid radicals is present. (a) Colourless, odourless gas turns lime water The acid radical may be CO32- or HCO3- milky (b) Colourless with rotten eggs smell and turns Sulphide(S2-) is confirmed. lead acetate paper black. (c) Colourless gas with suffocating smell. Heat and pass the gas through acidified K2Cr2O7 SO32- is confirmed. solution. The solution turns green (d) Colourless gas with suffocating smell with a yellow ppt. of sulphur in the test tube. Heat and S2O32- is confirmed. pass the gas through acidified K2Cr2O7 solution. The solution turns dark blackish green. (e) Colourless gas followed by brown gas and it NO2- is confirmed. turns starch iodide paper blue. (f) Colourless gas with the smell of vinegar. The acid radical may be CH3COO- Tests to distinguish between CO32- and HCO3- EXPERIMENT OBSERVATION INFERENCE Salt + water, boil and pass the (a) Lime water does not turn milky. CO32- is confirmed. gas through lime water (b) Lime water turns milky. HCO3- is confirmed. Confirmation test for Acetate EXPERIMENT OBSERVATION INFERENCE Salt solution + Neutral FeCl3 sol. Appearance of blood red colour. Acetate is confirmed -1-  SECOND GROUP OF ACID RADICALS The acid radicals involved in this group are Cl-, Br- and NO3-. The group reagent is concentrated sulphuric acid (H2SO4). EXPERIMENT OBSERVATION INFERENCE 2nd group Acid radical is Effervescence with colourless or coloured gases present (a) Colourless gas with a pungent smell and gives dense Salt + white fumes when a glass rod dipped in ammonium The Acid radical may be Cl- Concentrated hydroxide (NH4OH) is exposed. H2SO4 and heat if necessary. (b) Brown gas and the solution is not blue. The acid radical may be Br- (c) Light brown gas and brown gas with pieces of copper The Acid radical may be NO3- turnings and the solution turns blue in the test tube. Confirmation test for Chloride EXPERIMENT OBSERVATION INFERENCE (a) Chromyl – Chloride test: Salt + few Red vapours are obtained. K2Cr2O7 crystals + conc. H2SO4 and heat Pass the vapours through the test tube The solution turns yellow. which contains NaOH solution. Chloride is confirmed. To this yellow solution, add dilute Yellow ppt. is formed CH3COOH and lead acetate solution. (b) Silver Nitrate test: Salt solution + White ppt. is formed Chloride is confirmed. AgNO3 solution + dilute HNO3 which is soluble in NH4OH. Confirmation test for Bromide EXPERIMENT OBSERVATION INFERENCE (a) Globule Test: Aqueous solution of salt + two An orange-red globule is drops of CCl4 + 1ml chlorine water and shake Bromide is confirmed. obtained well. (b)Silver Nitrate test: Salt solution + AgNO3 A pale yellow ppt. slightly soluble Bromide is confirmed. solution + dilute HNO3 in NH4OH is obtained. Confirmation test for Nitrate EXPERIMENT OBSERVATION INFERENCE Brown ring test: Strong solution of the substance + 2 or A brown ring is formed 3 drops of conc. H2SO4, and cool. Add freshly prepared at the junction of two Nitrate is confirmed. FeSO4 solution on the sides of the test tube. liquids. -2-  THIRD GROUP OF ACID RADICALS The basic radicals involved in this group are SO42- and PO43-. EXPERIMENT OBSERVATION INFERENCE Test for Sulphate: Aqueous solution of salt + dilute A white ppt. insoluble in dilute Sulphate (SO42-) is HCl + BaCl2 solution. HCl is obtained confirmed. Ammonium – Molybdate Test: 2ml of soda extract 1 + A canary yellow precipitate is Phosphate (PO43-) is dilute HNO3 + Ammonium Molybdate solution. obtained. confirmed. 1 Soda extract to be prepared if the given salt is partially soluble in water. ANALYSIS OF BASIC RADICALS OR CATIONS This is classified into 6 groups. They are mentioned as below: GROUP RADICALS GROUP REAGENTS 2+ + I Pb ,Ag Dilute Hydrochloric acid(HCl) II Pb2+ ,Hg2+ ,Cu2+ ,Cd2+ Dilute HCl + H2S gas. 3+ 2+ 3+ III Al ,Fe , Fe NH4Cl(s) + NH4OH 2+ 2+ 2+ 2+ IV Zn ,Mn ,Co ,Ni NH4Cl(s) + NH4OH + H2S gas 2+ 2+ 2+ V Ca ,Sr ,Ba NH4Cl(s) + NH4OH + (NH4) 2CO3 2+ + VI Mg , NH4 -Nil- Preparation of Original solution: A suitable solvent is found for the salt as given in the preliminary test. A few drops are used as solution. Test for NH4+ Radicals: This test is carried out before starting the analysis for the basic radicals. EXPERIMENT OBSERVATION INFERENCE (a) Salt + NaOH solution and heat it. Colourless gas with a pungent smell is obtained. NH4+ may be present in the Expose a glass rod dipped in conc. Dense white fumes and moist red salt HCl to the gas and moist red litmus litmus paper turns blue paper. (b) Original solution + Nesseler’s Brown solution or ppt. is obtained NH4+ is confirmed. reagent. FIRST GROUP OF BASIC RADICALS The basic radicals of this group are Pb2+ & Ag+.The group reagent is dilute HCl. EXPERIMENT OBSERVATION INFERENCE (1) Original solution + Dilute HCl White ppt. is formed. May be Pb2+ & Ag+ (a) ppt. dissolves in hot water. May be Pb2+ Filter and add water to ppt. and heat (b) ppt. is insoluble in water. May be Ag+ (a) A yellow ppt. is formed. (2) Original solution + Potassium Pb2+ is confirmed. Chromate solution. (b) A brick red ppt. is formed. Ag+ is confirmed. (3) Original solution + KCl sol. A yellow ppt. soluble in hot water, on cooling reappears as golden yellow spangles. ppt. obtained + water and Pb2+ is confirmed. The yellow ppt. is insoluble heat it. in hot water. -3-  SECOND GROUP OF BASIC RADICALS The basic radicals of this group are Pb2+, Hg2+, Cu2+ and Cd2+.The group reagent is Dilute HCl + H2S gas. EXPERIMENT OBSERVATION INFERENCE (a)A Black ppt. is observed. May be Pb2+ Hg2+ & Cu2+ Original solution + Dilute HCl + H2S gas. (b)A yellow ppt. is observed. May be Cd2+ The identification of Pb2+, Hg2+, Cu2+ and Cd2+ are as follows: EXPERIMENT OBSERVATION INFERENCE (a) Original solution + Potassium A yellow ppt. is observed. Pb2+ is confirmed. Chromate. A bluish white ppt. soluble in excess (b)Original solution + NH4OH of NH4OH is observed which gives May be Cu2+ rise to a deep blue solution. (c) Original solution + dil. acetic A chocolate red ppt. is observed. Cu2+ is confirmed. acid + potassium Ferro cyanide sol. (d) Dissolve the black ppt. in aqua A white ppt. is observed which turns regia 2 + 1ml of distilled water, Hg2+ is confirmed. grey. heat & add 2 drops of SnCl2 (e) Original solution + dilute acetic acid + H2S gas. A yellow ppt. is formed. Cd2+ is confirmed. 2 Aqua regia is mixture of 3 drops of HCl + 1 drop of HNO3 THIRD GROUP OF BASIC RADICALS The basic radicals of this group are Al3+, Fe2+ and Fe3+.The group reagent is NH4Cl + NH4OH EXPERIMENT OBSERVATION INFERENCE (1) Original solution + (a) A white gelatinous ppt. is obtained. May be Al3+ NH4Cl(s) + NH4OH in (b) A dirty green ppt. is obtained May be Fe2+ excess (c) A reddish brown ppt. is obtained May be Fe3+ (a) White gelatinous ppt. soluble in excess of NaOH The basic radical is Al3+ is obtained which gives a colourless sol. (2) Original solution + (b) Dirty green ppt. insoluble in excess of NaOH The basic radical is Fe2+ NaOH solution (c) Reddish brown ppt. insoluble in excess of NaOH The basic radical is Fe3+ (3) Clear solution of 2(a) + solid NH4Cl and The white gelatinous ppt. reappears. Al3+ is confirmed. heat (4) Original solution + acidified KMnO4 solution (a) The pink colour of KMnO4 is not discharged. Fe3+ is confirmed. which is added drop wise. -4-  FOURTH GROUP OF BASIC RADICALS The basic radicals of this group are Zn 2+, Mn2+, Co2+ & Ni2+.The group reagent is NH4Cl + NH4OH And H2S(g). EXPERIMENT OBSERVATION INFERENCE (a) a white ppt. is obtained May be Zn2+, Mn2+ or Co2+ (1) Original solution + NH4Cl(s) + NH4OH in excess + H2S(g) (b) Buff or pale pink or flash coloured ppt. May be Mn2+ soluble in dilute HCl is obtained. (a) The white ppt. is soluble in excess of Zn2+ is confirmed (2) Original solution + NaOH NaOH giving a colourless solution. solution+. (b) The white ppt. insoluble in excess of Mn2+ is confirmed NaOH but turns brown. (3) Dissolve the 1(a) in aqua regia, evaporate to Dryness, add 1ml of distilled water and divide the resultant product into two parts. Part (1) + 1 ml of amyl alcohol + 100 mg of solid A Blue colour in the alcohol Co2+ is confirmed NH4SCN and stir it. layer is obtained. Part (2) + 5 drops of dimethyl glyaxime reagent + A pink ppt. is obtained. Ni2+ is confirmed. NH4OH. FIFTH GROUP OF BASIC RADICALS The basic radicals of this group are Ca2+, Sr2+ & Ba2+.The group reagent is NH4Cl(s) + NH4OH and (NH4)2 CO3. EXPERIMENT OBSERVATION INFERENCE (1) Original solution + NH4Cl(s) + NH4OH in May be Ca2+, Sr2+ or (a) A white ppt. is obtained. excess + (NH4)2 CO3 solution. Ba2+ (2) Dissolve the white ppt. obtained in small amounts of dilute acetic acid. Divide the solution in three parts. Part (1) + Potassium chromate solution. A yellow ppt. is obtained. May be Ba2+. Part (2) + Calcium Sulphate Sol. and heat. A thin white ppt. is obtained. May be Sr2+. Part (3) + Ammonium exalate solution. A white ppt. is obtained. May be Ca2+. (a) Apple green coloured flame is (3)Flame tests: Make a paste of the given Ba2+ is confirmed. obtained. salt with few drops of Conc. HCl in a watch glass. Heat a Pt. wire in non luminous flame (b) Crimson red coloured flame is Sr2+ is confirmed. till no colour is imparted to the flame. Dip obtained. the Pt. wire in the paste and hold it in the (c) Brick red coloured flame is flame. Ca2+ is confirmed. obtained, SIXTH GROUP OF BASIC RADICALS EXPERIMENT OBSERVATION INFERENCE (1) Original solution + excess of NH4OH + A white ppt. is obtained. Mg2+ is confirmed. Ammonium Hydrogen Phosphate. ______________________________________________________________ -5-