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YANDALKA LIMETRY, , acid is known as, , rd alkali is known as, mon indicators, , A. ACIDIMETR, , Estimation of alkalies using standard, , acidimetry and estimation of acids using standa, alkalimetry. Phenolphthalein or Methylorange are the, , used in acidimetry and alkalimetry., , Experiment No.1, Standardization of Hydroch, , Find out the molarity, supplied with pure anhydrous Sodium carbonate., , loric acid with standard Sodium carbonate., , of the given Hydrochloric acid. You are, , Principle, The experiment is based on the reaction between H, acid and Sodium carbonate according to the equation., , 2HCI + Na,CO, — 2NaCl +H,0 + co,, , (2 moles) (1 moles), , Molarity equation for the above estimation is 2x(V,M,)=1 x (V,M,), where V, in the Vol. of Na,CO, and M, is the Molarity of Na,CO, and V,, is the Vol.of HCI and M, is the Molarity HCl., , The above relationship can be also derived from the following, equations. At the end point; from the balanced equation:- ‘, , Volume of HCI X Molarity of HCl = Volume of Na,CO, x Molarity of Na,CO,, 2 i, : 1, ie. V,XM, ~ V,XM,, 2 ia 1, , ydrochloric, , , , ie. 2x(V,M,)=1 x (V,M.,), , A standard solution of Sodium carbonate is prepared and a known, , volume of it is titrated agains! i i, quae gainst the given HCI using Methyl orange a5

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29, , Procedure, , (a) Preparation of a a Standard solution of Sodium carbonate, , About 0.53 g ie. Go x 100) of pure dry (A.R. quality) Sodium, , carbonate is taken in a clean dry weighing bottle and is weighed, accurately. It is then transferred very carefully into a funnel placed over, 100 mi standard flask. The weighing bottle is then weighed accurately., The difference between the two weights gives the exact weight of Sodium, carbonate transferred into the standard flask. The Sodium carbonate, in the funnel is carefully washed down into the flask using a jet of, distilled water froma wash bottle. The funnel and its stem are also, , ved. The, , carefully washed down into the flask and the funnel is remo, , Sodium carbonate is dissolved completely by gently giving the flask a, ater is then added to the flask and the, , to the mark. The flask is then stoppered, rm in, , rotatory motion. Distilled w, , solution is carefully made up, and carefully shaken well ‘so that the solution becomes unifo, , - concentration., , , , , , Article ., weighed Total wt., , , , Weighting, bottle+, Sodium, carbonate, , Weighting, bottle, alone, , , , , , , , , , , , Wt. of Sodium cabonate = ............ g.

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JO, , (bd) Quedardization af HC 7, A clean burette Is rinsed with a little of the given HCI and it js, , then filled with it,, , A clean 20 mb pipette Is rinsed with the standard Sodium, carbonate solution, 20 mL of the solution is then pipetted out into a, clean conical flask, One or two drops of Methyl orange (indicator) is, added to it which imparts a golden yellow colour to the solution. It is, then titrated against the HCI from the burette after noting the initial, reading of the burette, The end point is when the golden yellow colour, just changes to pale red orange. The burette reading is noted. The, titrations are repeated till concordant values are obtained., , , , , , HCI x Na,CO, Indicator : Methyl! Orange, Vol.of Burette Reading Vol. of, a Na,CO. ., ada Initial Final HCl, , mt