Determination of pKa and pKb Using Acid-Base Titrations Lab Report Objectives: This experiment aims at determining the concentration of acid-base equilibrium constants for acetic acid and aqueous ammonia using titration curves. Introduction: The main objective in the volumetric titration of an acid with a base is the determination of the equivalence point. The equivalence point is a point where the acid has been fully neutralized by the base. One can determine the completeness of the reaction by adding an indicator that changes when the reaction is approaching an equivalence point. Furthermore, the completeness of a reaction can be determined by a pH meter.
Decomposition of Aspirin Studied with UV/Visible Absorption Spectroscopy Aims: To determine the concentration of salicylic acid, formed from the hydrolysis of Aspirin, at regular intervals using the UV/Visible Absorption Spectroscopy From the concentration of salicylic acid, concentration of Aspirin to be determined using an equation Calculate the rate constant of this reaction and its order from a plot of graph of ln(aspirin) vs time Discuss the overall flaws and improvements to the experiment Results: As per schedule1, 0.212g of aspirin was added to 50 ml boiling water to form salicylic acid in a 100 ml flask, of which 1 ml was then pipetted to a 50 ml volumetric flask at the 5th min. Following an ice bath, the solution was mixed
Test for phlobatannin An aqueous extract of the plant sample was boiled with 1% aqeous hydrochloric acid and deposition of red precipate was taken as evidence for the presence of phlobatannins. Test for Terpenoids 5ml of each extract was mixed in 2ml chloroform, and concentrated H2 504 9 (3ml) was carefully added for form a layer. A reddish brown colouration of the interface
Briefly, a solution containing 0.3 gr (3 mmol) succinic anhydride and 0.4 ml (3 mmol) of triethylamine in 10 ml of THF was dropwise added to a stirred solution of 1 mmol of sPEG in 10 ml of anhydrous THF for 12 h at 75 C. The solvent of product solution was evaporated by a rotary evaporator and the obtained dark yellow viscous liquid was dissolved in acidic water (pH= 3). In the following,
3.7.1 Fehling’s Test 5mL of freshly prepared Fehling’s solution was boiled then added with an equal quantity of plant extract and boiled again. Positive result: Brick red precipitate indicated the presence of reducing sugars. 3.7.2 Molisch’s Test The 2mL of the prepared filtrate was mixed with 0.2mL of alcoholic solution of 10% alpha-naphthol in addition to 2mL sulfuric acid. Positive result: Bluish violet zone is formed and this indicate the presence of carbohydrates and glycosides. 3.7.3 Benedict’s Test 1mL of the filtrate was added to 5mL of Benedict’s reagent and then the mixture was heated.
The cellulose corresponds to the insoluble fraction of the samples. The determination of hemicelluloses (pentosanes) was carried out according to the standard NFT 12-008.Hydrobromic acid is used to heat the samples. The hemicellulose was transformed in to the furfural. It was later extracted by distillation process and measured by
In order to synthesize this compound, measure out 1 gram of NaC2H3O2.Weighed 1 gram of NaC2H3O2 and mixed it with ionized water. Boiled 12 mL of 1.0M Acetic Acid added into a beaker containing the sodium carbonate on a hot plate until all the liquid is evaporated leaving solid precipitate form inside of the beaker. Weigh the precipitate form and mix it with water until fully dissolved. Weigh the precipitate remaining. A flame test and a halide ion test were performed.
126.96.36.199. (C) Test for flavanoids ( Sofowara, 1993; Harbrone, 1973): Three methods were used to determine the presence of flavonoids in the plant sample.5 ml of dilute ammonia solution were added to a portion of the filtrate of each plant extract followed by addition of concentrated H2SO4. A yellow colouration observed in each extract indicated the presence of flavonoids. The yellow colouration disappeared on standing. Few drops of 1% aluminium solution were added to a portion of each filtrate.
In a typical procedure, equimolar zinc nitrate hexahydrate [Zn(NO3)2, 6H2O] and hexamine (HMT) [(CH2)6N4] were dissolved in 80 ml D.I. (deionised) water to form a 0.04 M solution. Thereafter the solution was kept in a Pyrex bottle and heated in a regular laboratory oven at 110°C for 6 h. Finally the bottle was naturally cooled down and the product was collected by filtering and washing with copious amount of D. I. water. For the synthesis of ZnO-silica hybrid, 5 ml TEOS was dissolved in 40 ml ethanol via sonication followed by which 1 ml D.I. water and 2 ml ammonia was dropped into the solution in stirring condition one after another.
2ml of 10% ammonium citrate was added to each beaker. The pH was then adjusted to 8.5 by adding 10 drops of 5M NH4OH(aq) to each beaker. 3ml of 0.1% cuprizone was added to each beaker. The four solutions were then transferred to 25ml volumetric flasks. The beakers were washed with de-ionized water, and the washings were combined with the solutions in the 25ml volumetric flask.