PH Titrations Lab Report Example | Topics and Well Written Essays - 1000 words

PH Titrations - Lab Report Example In the chemistry of acids and bases, titration is used in determining the value of pH for different solutions (Verma, D. 2006). Whenever we carry out an acid-base titration, an indicator is normally used in telling whether the solution is an acid or a base. In other cases an indicator may change its clear a process that is described as a titration end point. In many cases, color changes may be observed in mixing two solutions together in the proportions that are exact. Such a mixture may be defined as an equivalence point. In order to gain more understanding on titrations, an experiment was set to investigate the pH values for different solutions. Hypothesis The hypothesis of the study was to determine the pH at the equivalence point and the unknown concentration of the acids Aim The aim of the study was to find out the pH at different points of the unknown acids concentration. Methodology. Apparatus. The instruments and the apparatus used in this study include Bulb Pipette, burette, conical flask, 3 substances; HCl, NaOH, and CH3COOH, beaker, electrode, Magnetic, stirrer, and the pH meter. Procedure The burette was filled with 1,0 mol of sodium hydroxide dm-3 up to a zero mark. The conical flask was also filled. About 25cm3 of 0.1 moldm-3 of HCl was added using a pipette. The flask was placed on a magnetic stirrer, and the stirrer dropped back into the flask. The stirrer was turned on in the medium to avoid movements of the bar to hit the glass. The titration was them started with a similar volume to that in the table. After each titration the pH for each solution was recorded. The process was repeated for vinegar and hydrochloric acid. The collected data was presented in table 1 and 2 in the results section. Table 1: pH values for HCl V of NaOH PH of HCl 0 1,86 1 1,91 2 1,98 2.5 2,03 3 2,09 3.5 2,22 4 2,43 4.2 2,53 4.4 2,74 4.5 2,96 4.6 3,29 4.7 5,10 5 10,85 5.5 11,44 6 11,64 7 11,46 CV=CV NaOH Acid HCl 4,7x0,514=25xC C of HCl=0,0966 Table 2: pH values of CH3 COOH V of NaOH PH of CH3COOH 0 2,91 1 3,76 2 4,36 2.5 4,58 3 4,84 3.5 5,10 4 5,70 4.2 6,38 4.4 10,15 4.5 10,60 4.6 10,75 4.7 10,90 5 11,10 5.5 11,43 6 11,61 7 11,81 NaOH CH3COOH 4,3x0,514 = 25xC C of CH3COOH=0,0884 Graph 1: A graph of base versus strong acid Graph 2: A graph of a weak acid and a base. Discussion In this experiment the set up was used in calculating the quantity of the acid that is unknown inside the receiving flask through measuring the quantity of the tyrant or the base taken for the acid to be neutralized. In many cases, there are two categories of methods used to identify a neutralized solution. The first method involves using a pH meter inside the receiving flask and adding the base up to when the value of the pH reads 7. Another method uses an indicator (Matar, S. 2001). In this case, an indicator is a base or an acid having a conjugate base or acid with a color different from that of a compound that is original. There would be some changes in the color when th e solution has a one to one ratio of the mixture of the different forms of colored indicators. From the equation of the Henderson-Hasselbatch, the pH of the solution would be equated to the pH of the indicator when the indicators’ end point is realized. At this point, the solution’s pH and the titrand’s volume would be identified, and the amount of base needed for neutralization of the solution that is not known can easily be deduced. The obtained data was