Standardization of NaOH Solution Using Oxalic Acid

             Results:.
             Pipette Solution: NaOH.
             Pipette Volume: 25ml ©Ã¸.
             Burette Solution: Oxalic acid solution.
             Indicator: Phenolphthalein.
             .
             Rough reading = 24.6 ml.
             Accurate reading 1 = 24.5 ml.
             Accurate reading 2 = 24.5 ml.
             Accurate reading 3 = 24.6 ml.
             Concordant results = (24.6+24.6+24.5+24.5)/4 .
             Average volume of Oxalic acid solution added = 24.55 ml.
             Analysis:.
             2NaOH + COOH COO-Na+ + 4H2O.
             I I.
             COOH COO Na.
             From the equation: 2M NaOH = 1M (COOH).
             No. of moles of (COOH) ©u H ©uO = Concentration of solution
             • Volume .
             I.e. no. of moles of(COOH) ©u H ©uO = .05
             • (24.55/1000).
             = 0.001275 moles.
             The number of NaOH moles must be double this value because the equatio makes the ratio out to be 1: 2.
             No. of moles of NaOH = Number of moles of (COOH) ©u H ©uO
             • 2.
             I.e. no. of moles of NaOH = ((0.001275
             • 2)
             •1000)/25.
             = .102 moles.
             .
             After analyzing the results we can use our answers to figure out the percentage error for this experiment. .
             The results indicate that the concentration of our solution of NaOH is .102M/dm ©Ã¸. However we know that the value of the NaOH solution is about .1M/dm ©Ã¸. Therefore we can work out the error in our results. .
             % Error in results = Difference in concentration The actual concentration
             • 100.
             % Error in results = (.002/.1)
             • 100.
             = 2%.
             Error Analysis:.
             Chemical balance is ¾ 0.01g, .
             Measures Value = 1.58g .
             (.01
             • ¬ 1.58)
             •100 = 0.63% .
             250ml volumetric flask is ¾ 0.25ml .
             Measures Value = 250ml.
             (.25/250)
             •100 =.0006%.
             25ml pipette ¾ 0.025ml.
             Measures Value = 25ml.
             (.025
             • ¬ 25)
             •100 = 0.001%.
             50ml burette ¾ 0.1ml.
             Measures Value = 50ml.