Based on the procedure background information and result , in your own words ple

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Based on the procedure background information and result , in your own words please state the procedure and conclusion of this lab, it's confusing for me! Thank you Experiment 7: Concentration of Acetic Acid in Vinegar Purpose Determine the amount of acetic acid in white vinegar by titrating with a solution of sodium hydroxide whose concentration is known. The indicator will be volume), the solution becomes basic and the indicator color changes to pink. This is an indication that the endpoint of the reaction has Background Information Titration is a volumetric technique used to the concentration of a soution by been reached and one has to stop adding any thhe more base If you have chosen the appropriate indicator, your endpoint should be very close to the equivalence point. At this point, the mole ratio of acid and base present in the resulting solution should be exactly the same with the stoichiometric ratio of the reactants - in our case, it is 1:1 measuring the volume of the solution required to react completely, with a measured mass (or A titration is meaningtul only it the following 1. The reaction must be completed: almost none reactant r uirements are met: Molarity-# mole / L of solution or. # mole-molarity x Lofsolution of the reactants should be left at the end of the reaction 2. The reaction should be relatively fast. 3. There should not be any side reaction(s) At the equivalence point, 4. There should be at least one method (visual or otherwise) to indicate that the reaction between the titrant and the analyte is or, MAVA -MaVg for our reaction You will need to do a pair of titrations that agrees within 0.15 mL in the volume of NaOH. These itrations, the molarity of the soltion of by using indicators that change color in excess sdium hydroxide and balanced equation, wil completed. The endpoint of a reaction can be determined acid or base. Typically this transition is very shar PrOvide all that you need to determine the molarity of the acetic acid. and you must not let your guard down if you want to catch the right moment. The equivalent point is when just enough strant is added to reach the correct stoichiometric ratio with the analyte. Theoretically, the endpoint measured by experiment is not necessarily the same as the epancy can be Procedure Getting Started 1. Obtain a 10-ml transfer pipet, a rubber bulb minimized by selecting an appropriate indicator and a 50-ml buret. 2, obtain about 30 ml of white 5% vinegar in a The object of this experiment is to determine the molar concentration of acetic acid (CH,COOH) in vinegar. You will accomplish this through the titration of a sample of vinegar with a solution of sodium hydraxide (NaOH). These substances clean dry beaker and about 85 ml of NaOH solution in a clean, dry Erlenmeyer flask that is closed with a rubber stopper Caution: NaOH solution used in this experiment is toxic and corrosive. Prevent contact with eyes skin, and clothing. Clean up any spills with copious amounts of water react readily The most commonly used indicator for strong acid/strong base or weak acid/strong base titration is phenolphthalein. The color of phenolphthalein changes from clear to pink as the medium changes Note: NaOH solution of known concentration must be protected when it is not in use. NaOH slowly absorbs CO2 in the air according to the following reaction: from acidic to basic. When the equivalence point absobs CO, in the air according to the following of the reaction is reached, the color of phenolphthalein may still be clear. However, when an additional drop of base is added (negligible 2 NaOH(s) + CO2(g) Nado,(aq) + Hon -47

Explanation / Answer

The current lab experiment is based on the volumetric quantitative estimation of concentration of an acid.

Titration is used when we have a solution of known concentration which can react fastly with the unkown concentration solution , and the completion of reaction can be accessed by use of suitable indicator.

In case of acid -base titration we use acid -base indicator like phenolphthalein.

Phenolphthalein is an indicator which gives pink colour in strongly basic conditions (like in presence of NaOH)

The indicator shows its colour just after the equivalence point

equivalence point is when the number of moles of base becomes equal to number of moles of acid

Moles of acid / or base = MolarityX volume (litre)

so at equivalence point

M1V1 = M2V2

As we have NaOH of known concentration (M1) and volume is noted from burette reading(V1) we have taken known volume of Acid (V2),

So we can calcualte the concentraiton of acid = M1V1 / V2

the process may be repeated again and the values obtained may be averaged to get the accurate concentration of acetic acid in the vinegar solution.

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