Discussion exp 1
- 1. Discussion: Titration is a technique for determining either the concentration of a solution of unknown molarity or the number of moles of a substance in a given sample. A chemical reaction is used for this purpose, and the reaction must be fast, be complete, and have a determinable end point. The reactions of strong acids and bases generally meet these criteria, and acid-base titrations are among the most important examples of this technique .In this experiment, the sample is hydrated oxalic acid and sodium hydroxide. The sodium hydroxide as base substance and hydrated oxalic acid as acid substance where the concentration of hydratedoxalic acid is unknown. Given that, the concentration of the base are 0.2 M . Eq: An indicator is used as signal the point which the titration is stopped. the indicator that we use in this experiment is phenolphthalein. If we use base as titrant, and acid as solution in the Erlenmeyer flask, at the end point, the solution in the Erlenmeyer flask will turn to light pink. If we use acid as titrant, and base as solution in the Erlenmeyer flask, atthe end point, the solution in the Erlenmeyer flask will turn to colourless. For this experiment, the solution turn from the colourless to light pink because we use the base as titrant. From the experiment that we did, the actual molarity of naoh solution that we get is 0.21M. If we double the mass of hydrated oxalic acid, the molarity will be 0.1M due to double of volume of naoh used during the titration. Is it unnecessary for us to know the exact concentration of oxalic acid solution in order to determine the concentration of the base because the mol of acid cannot change when we dissolve the mass of oxalic acid in the unknown volume of water In this experiment, there are some mistake like use more than acid v o l u m e t o t i t r a t e solution of NaOH. The volume has pass the end point, so the volume uses is much more than needed. So, the colour has changed to dark purple from light pink. To overcome this problem, we can titrate slowly and shake the volumetric flask for about 30 second when the solutions show changing in colour from colourless to light pink. The other r e a s o n s i s t h e u s i n g o f v o l u m e t r i c f l a s k t h a t ’ s h a d b e e n u s e d w i t h o t h e r s o l u t i o n . S o , t h e concentration of newest solution will affect. To overcome this problem, we must make sure the volumetric flask is totally clean and dry. That’s problems had affect our result. That’s why ourr e s u l t i s n o t p r e c i s e a n d accurate to the correct value. There is some recommendation for this experiment. First, we must ensure that there are no bubbles trapped at the tip of the burette during the filling of naoh solution. Second, we must avoid from make a parallex error for most of the measured content. Third, the
- 2. naohsolution is titration drop by droop when there are change colour of t h e a c i d i n t h e c o n i c a l f l a s k . L a s t l y, w e m u s t t a k e e a c h m e a s u r e m e n t must be sharply as can so that the final result being better. References: 1. http://www.easychem.com.au/the-acidic-environment/acid-base- definitions/titration-technique 2. Fundamental of Chemistry, David E. Goldberg, McGraw Hill, 303