Acid Base Titrations
Najib Chowdhury CHM1311-C03 Yayha Albkuri
Introduction:
Acids and Bases
The experiment involves with the investigation of the unknown solutions used and the determination of their concentrations. The techniques and their expected outcomes are elaborated further in detail in the following report. For the most part, Arrhenius’s definition of an acid and base is employed in this experiment as it is sufficient for this case. Acid can be represented visually using this equation:
〖HNO〗_3 (aq)⟺ H^(+ ) (aq)+ 〖〖NO〗_3〗^- (aq)
As per Arrhenius’s definition, HNO3 donates its H+. Likewise, the base has the same underlying design. In this case, NaOH donates a hydroxide ion.
NaOH (aq)⟺〖Na〗^+ (aq)+ 〖OH〗^(- ) (aq)
Concentration
For determining the concentration of an acid, it is imperative that the amount (in moles) of an acid being used is known that is being mixed with a certain amount of water (in litres). The equation for concentration is:
Concentration (mol/L)=(amount of acid(mol))/(volume of water (L))
Safety Precautions:
The experiment deals with the use of organic solutions that are corrosive in nature, the use of extra precautions is strongly advised. It is highly recommended that the magnetic stirrer is not disturbed during the dissolution of different solution, as
1. To prepare a standard solution of oxalic acid and use it to standardize an unknown sodium hydroxide solution.
The purpose of this experiment is to examine the stoichiometric relationship between reagents and the identity of the products by using three acid/base neutralization reactions of a triprotic acid, phosphoric acid, and varying molar equivalents of sodium hydroxide. The data will be used to determine the formula weight of the products and identify the remaining salt for all three reactions.
In reference to the analysis of anions, Table 1 shows that a precipitate was formed when our unknown was combined with HNO3 and AgNO3, thus indicating the presence of a chloride ion. Because our unknown did not form a precipitate due to HCl and BaCl2, separate, effervesce, or smell, we concluded that neither sulfate, nitrate, carbonate nor
12. Write the balanced chemical reaction of the product of the reaction described above (problem 11) with NaOH. Is the product of this reaction soluble in aqueous solution?
One of the most important skills to have in the chemistry lab is the understanding of how chemicals will react. Knowing for example, how a chemical will react with a metal, is an excellent way of determining the amount of a particular metal in a deposit. This knowledge was used in this lab to determine the amount of copper in an unknown sample mixture. It is also known that the determination of the percent concentration of a certain solution, will directly effect the percent transmission and absorption of a solution, dependent upon its dilution. By first testing known concentrations of a solution, and plotting this information graphically, a line is formed
The problem that was trying to be solved in this study deals with analyzing unknown solutions. In this particular case, a chemical company has several unknown solutions and to correctly dispose of them they need to know their properties. To figure out the properties several qualitative tests were performed throughout the study (Cooper 2012).
Three grams of a mixture containing Benzoic Acid and Naphthalene was obtained and placed in 100 ml beaker and added 30 ml of ethyl acetate for dissolving the mixture. A small amount (1-2 drops) of this mixture was separated into a test tube. This test tube was covered and labelled as “M” (mixture). This was set to the side and used the following week for the second part of lab. The content in the beaker was then transferred into separatory funnel. 10 ml of 1 M NaOH added to the content and placed the stopper in the funnel. In the hood separatory funnel was gently shaken for approximately one minute and vent the air out for five seconds. We repeated the same process in the same manner one more time by adding 10ml of 1M NaOH.
The purpose of this experiment was to determine the pKa, Ka, and molar mass of an unknown acid (#14). The pKa was found to be 3.88, the Ka was found to be 1.318 x 10 -4, and the molar mass was found to be 171.9 g/mol.
The purpose of this lab was to experiment with triprotic acid to create different salts through neutralization. Specifically, using varying volumes of sodium hydroxide with a constant 1 mL of 6M Phosphoric acid. In doing so one can examine the reactions and use stoichiometry to identify the products formed from the relationship between the reagents.
By using acid-base titration, we determined the suitability of phenolphthalein and methyl red as acid base indicators. We found that the equivalence point of the titration of hydrochloric acid with sodium hydroxide was not within the ph range of phenolphthalein's color range. The titration of acetic acid with sodium hydroxide resulted in an equivalence point out of the range of methyl red. And the titration of ammonia with hydrochloric acid had an equivalence point that was also out of the range of phenolphthalein.. The methyl red indicator and the phenolphthalein indicator were unsuitable because their pH ranges for their color changes did not cover the equivalence points of the trials in which they were used. However, the
The styrofoam cups were used to store the acid (cup was labeled A) and base (cup was labeled B) prepare for them to be mixed. A lid was put on cup A and then the temperature probe was inserted to begin to measure the temperature
The purpose of this lab was to perform acid base titrations using a pH electrode to monitor the equivalence point. Standardized NaOH was titrated with HCl and acetic acid using phenolphthalein as the indicator. Each titration was analyzed by the following plots to determine the equivalence point volume: pH vs volume, first and second derivative plot and Gran plot.
In this lab a acid-base indicator phenolphthalein was used to determine endpoint of a reaction HCl(aq) and KOH(aq). At the end point all of the HCl(aq) would have reacted with KOH(aq), and the pH becomes 7. The phenolphthalein would changed colours from colourless to pink indication when enough KOH(aq) was added. The purpose of numerous trials was to use the average volume of the 3 trials with similar measurements.
5. a) H2SO4 is a strong acid just like HNO3 but it is a polyprotic acid meaning that their will be two proton transfer reactions and thus two equivalence points.
1.3.2 The next step when determining the molarity of NaOH(aq) was to calculate the moles of HCl(aq) by using the volume HCl(aq) provided on the lab scripts and the molarity obtained from the bottle of HCl(aq) used during the investigation. The eq.5 and eq.6 below was used to calculate: