• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

To determine the concentration of acetic acid in an unknown sample of vinegar by titrating a known volume ofthe acid solution against a standardized basic solution.

Extracts from this document...


S.6A Karen Kwok (8) VA2 22th, September, 2002. Chemistry Laboratory Report Title: Acid-base Titration Date: 20th, September, 2002. Objective: (1) To determine the concentration of acetic acid in an unknown sample of vinegar by titrating a known volume of the acid solution against a standardized basic solution. Procedures: Part A: Standardization of 0.1M sodium hydroxide solution using potassium hydrogen phthalate as the primary standard. 1. 5.010g of analytical grade potassium hydrogen phthalate was weighted and dissolved in deionized water in a beaker. 2. After all the KHC8H4O4 was dissolved, the solution was then transfer to a 250 cm3 volumetric flask. 3. Then the volumetric flask was filled to the graduation mark with deionized water. 4. The volumetric flask was stopped. The flask was turned upside down in order to mix the solution well. 5. 25 cm3 of KHC8H4O4 solution from the volumetric flask was transfered in a conical flask using a pipette and pipette filler. 6. ...read more.


Therefore the average volume of 0.0500 M sodium carbonate required for neutralization: = 25.55 + 25.30 +25.50 3 cm3 =25.45 cm3 No. of moles of 250 cm3 KHC8H4O4 in volumetric flask = Mass Molar Mass = 5.010 204.23 mol =0.025 mol No of mole of 25 cm3 of KHC8H4O4 =0.025 � 25 250 =0.0025mol According to the equation, 1 mole of NaOH required 1 mole of KHC8H4O4 for complete neutralization. ?No of moles of NaOH= 0.0025mol Molarity of NaOH solution = No. of moles of NaOH Volume of solution = 0.0025mol 0.02545dm3 =0.098M The volumes of 0.098M NaOH solution required for neutralization are: 24.50 cm3, 22.65 cm3. Therefore the average volume of 0.098M sodium hydroxide required for neutralization: = 24.50 + 22.65 2 cm3 = 23.58 cm3 NaOH (aq) + CH3COOH(aq)?CH3COONa (aq) + H2O(l) 0.098M ?M 23.58 cm3 25 cm3 No. of moles of NaOH in 23.58 cm3 = Molarity of solution �Volume of solution = 0.098 mol dm3 �0.02358 dm3 = 0.0023mol According to the equation, 1 mole of NaOH required 1 mole of CH3COOH for complete neutralization. ...read more.


Potassium hydrogen phthalate can be act as a primary standard to standardize NaOH. It is because it is a monoprotic acid whose formula is KHC8H4O4 and has a high molecular weight (204.22 g/mol). Also, the exact mass can be easily determi ned by weighing the dried acid on an analytical balance. It is stable and not hydroscopic, and it fits all the propeties of a primary standard. 3. Is methyl orange a suitable indicator in this experiment? Why? Ans: Methyl orange is not a suitable indicator in this experiment. Because for strong base (NaOH) with weak acid (KHC8H4O4), the pH at the equivalence point is always greater than 7 because of the conjugate base is basic. And from the titration curve for strong acid with weak base, we know that pH at the equivalence point is approximately 8.8, and the dramatic change in pH cannot cover the pH range of methyl orange which is (3.1-4.4). But it can cover the pH range of phenolpthalein (8.3-10.0), therefore it is more suitable for us to use phenolpthalein in this experiment. Titration for weak acid with strong base ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Aqueous Chemistry essays

  1. Marked by a teacher

    Investigate the effect of changing the concentration of sodium hydroxide (alkali) on the volume ...

    4 star(s)

    AGAINST THE VOLUME OF 1 MOLAR HYDROCHLORIC ACID IN (CM�) TO 1 MOLAR SODIUM HYDROXIDE. Volume of acid added (cm�) Test 1 Test 2 Test 3 Average temperature of reaction mixture in (�C) Temperature of reaction mixture (�C) Colour of indicator Temperature of reaction mixture (�C)

  2. Standardization of NaOH and Analysis of Unknown Acid Sample.

    2. Clean and rinse the 1-L bottle and stopper. Label the bottle "0.1 M NaOH". Put about 500mL of distilled water into the bottle. 3. Weigh out 4g (0.1 mol) of NaOH pellets and transfer them into the 1-L bottle. Stopper and shake the bottle to dissolve the sodium hydroxide.

  1. The Use of Volumetric Flask, Burette and Pipette in Determining the Concentration of NaOH ...

    Acids are paired with bases. One can accept a proton and the other can donate a proton. In the Lewis theory of acid-base reactions, bases donate pairs of electrons and acids accept pairs of electrons. A Lewis acid is therefore any substance, such as the H+ ion, that can accept a pair of nonbonding electrons.

  2. Determine the concentration or molarity of Ethanoic acid (CH3COOH) in two types of commercial ...

    To do this the process demonstrated in the plan has to be reversed, so: 0.9385 = to the no. mole in 1 dm3 (1000 cm3) and to be able to find out the percent mass data it is more convenient to know the no.

  1. In order to find out the exact concentration of sulphuric acid, I will have ...

    Before starting a new titration make sure that all the equipment is properly washed out. Although you can use an ordinary beaker for titrations, it might be a better idea to use a volumetric flask instead, because its shape makes it easier to swirl contents around and prevents any spillages at the same time.

  2. Obtain pure samples of Ethanol (CH3CH2OH) and Ethanoic Acid (CH3COOH) from fermented Yeast (Saccharomyces ...

    C6H12O6 2CH3CH2OH + 2CO2 + ENERGY (210KJ) Glucose Ethanol + Carbon dioxide + Energy The fermenter that was used contained a little magnet which was 'hopping' around inside the yeast solution as a result of repelling to a big stronger magnet on which the fermenter was resting on.

  1. Titrating Sodium hydroxide with an unknown molarity, against hydrochloric acid to find its' molarity.

    flask * Grade B, 50 cm� Burette excellent detail * Grade B, 25 cm � pipette * Pipette filler * Dropping pipette * Small filter funnel * 100 cm� beaker * Wash bottle and distilled water * Eye protection * Boss, clamp and stand * White tile * White card

  2. To carry out a titration between a strong acid and a weak alkali, to ...

    QUANTITY MEASURED PERCENTAGE ERROR (%) Mass of sodium carbonate using balance (0.005 x 100)/2.65 = 0.19% Volume of distilled water using graduated volumetric flask (0.5 x 100)/250 = 0.2% Transferring sodium carbonate solution using a pipette (0.5 x 100)/25 = 2% Carrying out the titration using a burette (0.005 x

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work