EXPERIMENT 3:ACID BASE TITRATION :DETERMINING OF THE CONCENTRATION OF HYDROCHLORIC ACID SOLUTION
1.To prepeare a standard solution of oxalic acid
2.To standardise 0.2M NaOH solution
3.To determine the concentration of HCl solution
4.To acquire the correct technique of titration
Titration is a technique used to determine the concentration of a solution using another solution with a known concentration.
Standard in basic titration:
One of the solution involve in a titration is used as standard solution .The standard solution can be classified as either primary or secondary.A primary standard solution is prepared by dissolving an accurately weighed pure solid of a known molar mass in a known volume of distilled water.
A primary standard is used to determine the molarity of the other standard solution,known as secondary standard.For example,oxalic acid,H2C2O4,,and potassium hydrogen phthalate,KHC8H4O4,are two common primary standards used to determine the concentration of bases (secondary standard).
Solution of NaOH and HCL used in titration need to be standardised because they contain impurities.Solid NaOH is hygroscopic(it absorbe moisture). Thus, it is difficult to obtain its accurate mass.The standardised based can then be used to determine the concentration of other acids.
Equivalance point and end point
An equivalent point is the point at which exact reaction accurs between the two reagent according to the stachiometry.To detect this equivalence point,an indicator which produces a change in colour is often used.the point at which indicator change colour is called the end point.The end point and equivalence point should ideally be the same.
In this acid –base titration,the neutralisation reaction involve are:
HCL(aq)+NaOH(aq) NaCL(aq)+H2O(l) ….(2)
(A)Preparation of standard solution
1. Mass of,3.25 g of hydrated...