![]() ![]() In case of soluble carbonate, this test is performed with water extract and in case of insoluble carbonates, this test is performed with the solid salt. HCl gives CO 2 gas that reacts with lime water to produce a white precipitate of calcium carbonate that turns lime water milky. Let us discuss the chemical reactions involved in the confirmation of Anions: Confirmation of Carbonate (CO 3 2-) (a) Reaction with di.l HClĬarbonate on reaction with dil. Chemical reactions involved in Potassium permanganate test This test helps in the detection of Cl -, Br -, I - and C 2O 4 2. This test is performed by using dilute sulphuric acid and potassium permanganate as reagents. H 2SO 4 test for SO 4 2-and PO 4 3- by performing their individual tests. If the salt does not react with dil H 2SO 4 as well as with conc. H 2SO 4 to evolve a mixture of carbon dioxide and carbon monoxide.ģ) Independent Group. (f) Oxalates: Oxalates salts react with conc. H 2SO 4 to produce vapours of acetic acid. (d) Nitrates: Upon reaction with conc.H 2SO 4 nitrates evolve NO 2 gas. (c) Iodides: Iodide salts react with conc. ![]() (b) Bromides: Bromide salts react with conc. H 2SO 4 to evolve hydrogen chloride (HCl) gas. (a) Chlorides: Chloride salts react with conc. H 2SO 4, warm a pinch of the salt with conc. ![]() H 2SO 4, nitric oxide (NO) gas is evolved which readly gives brown fumes of NO 2 with the oxygen of the air. (d) Nitrite: On treating solid nitrite with dil. (c) Sulphite: On heating solid sulphite with dil.H 2SO 4, SO 2 gas is evolved (b) Sulphide: Sulphides when treated with dil. (a) Carbonate: On treating the solid carbonate, CO 2 is given off in the cold with brisk effervescence. These gases on identification indicate the nature of the anion present in the salt. Chemical Reactions Involved in Dil.H 2SO 4 Test:ĭilute H 2SO 4 decomposes carbonates, sulphides, sulphites and nitrites in cold to give gases. Thus, these anions may be identified by performing the following tests below: 1) Dil. These are, therefore, identified by individual tests. SO 4 2- and PO 4 3- react neither with dil H 2SO 4 nor with conc.Cl -,Br -,I -,NO 3 - and C 2O 4 2- and CH 3COO - react with conc.H 2SO 4 to give out CO 2, H 2S, NO 2 and SO 2 gases respectively. CO 3 2-, S 2-, NO 2 - and SO 3 2- react with dil.The other preliminary tests are based on the fact that: The Dry heating test is one of the preliminary tests performed earlier which may give some important information about the acid radical present. The identification of the radicals is first done on the basis of the preliminary tests. (C) Identification of Anions (Acid Radicals) On heating, some salts undergo decomposition, thus evolving the gases. Quite valuable information can be gathered by carefully performing and noting the observations. This test is performed by heating a small amount of salt in a dry test tube. Characteristic smell helps to identify some anions such as acetate, sulphide etc. The physical examination of the unknown salt involves the study of colour, smell and density. (A) Physical Examination: Colour and Smell Some preliminary tests are done before going to the anion analysis. Qualitative Analysis of Anions Preliminary Tests Let's discuss the Qualitative Analysis of Anions. The procedure for detecting ions (cations and anions) in aqueous solutions are called Cation Analysis and Anion Analysis. It is mainly focused on detection of ions in an aqueous solution, so the substances in other states need to be converted into an aqueous solution before starting the experiment. The qualitative inorganic analysis is a method of analytical chemistry that seeks to find out the elemental composition of inorganic compounds through various reagents. The Theory What is Qualitative Inorganic Analysis? Our objective is to determine the anion present in the given salt. ![]()
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