Titration Of Ethandioic Acid With Sodium Hydroxide
2 NaOH + (COOH)2 Na2C2O4 + 2H2O
From the equation we can work out the required concentration of the Sodium Hydroxide
Approximate concentration of (COOH)2 = 0.03mol dm3
Therefore approximate concentration of NaOH = 2 x 0.03
= 0.06mol dm3
Therefore for this titration I will use Sodium Hydroxide with a concentration of 0.06mol dm3
Apparatus:
1 burette
1 25cm3 pipette
1 clamp stand
1 funnel
1 white tile
Phenolphthalein Indicator
Distilled water
Chemicals:
100 cm3 of solution containing ethandioic acid and sodium ethandioate
100 cm3 of sodium hydroxide with concentration 0.06mol dm3
Method:
Wash out the burette using a small amount of sodium hydroxide. Clamp the burette carefully making sure that the tap is closed and fill the burette using a funnel using the sodium hydroxide. Open the tap and let some of the sodium hydroxide run out into a beaker to fill the jet of the burette making sure that there are no air bubbles. Record the initial volume of sodium hydroxide in the burette, reading from the bottom of the meniscus and record to two decimal places.
Carefully place the pipette into to pipette filler and place it in the mixture of ethandioic acid and sodium ethandioate. Turn the thumb dial to suck up the solution. Suck up more solution than what is needed, remove the pipette filler and cover the to of the pipette with your index finger and apply pressure. By decreasing the pressure the level of the solution will fall. Carefully allow some of the solution out so that the bottom of the meniscus is in level with the like marked on the pipette. Transfer the solution in the pipette into a conical flask. Touch the end of the pipette against the inside of the conical flask to release the remaining mixture from the pipette. Add three to four drops of the phenolphthalein indicator to the mixture.
Place the conical flask on the white tile underneath the jet of the burette. Open the tap of the burette and allow about 2cm3 of the sodium hydroxide out into the conical flask, then swirl the solution. Repeat this until the solution in the conical flask is almost pink. Slow the flow of the sodium hydroxide so that it is coming out drop at a time swirling the solution all the time. As soon as the solution becomes pink it has reached the end point of the reaction. Stop the flow of sodium hydroxide and record the volume of sodium hydroxide left in the burette, then work out the volume of sodium hydroxide used.
Wash out the conical flask using distilled water and fill as before with the mixture and the phenolphthalein indicator. Top up the burette again recording the initial volume and repeat the titration. Repeat this process until you obtain results that are within 0.1cm3 of each other.
Titration Of Ethandioic Acid And Sodium Ethandioate With Potassium Manganate
2MnO4- + 5(COO-)2 + 16H+ 2Mn2+ + 10CO2 + 8H20
From the equation we can calculate the required concentration of the potassium manganate.
Approximate concentration of (COO-)2 = 0.06mol dm3
Therefore approximate concentration of MnO4- = 0.06 x 2
5
= 0.024mol dm3
Therefore for this titration I will use Potassium manganate with a concentration of 0.024mol dm3
Apparatus
1 burette (white markings)
1 25cm3 pipette
1 clamp stand
1 funnel
1 white tile
Distilled water
Chemicals
100 cm3 of solution containing ethandioic acid and sodium ethandioate
100 cm3 of potassium manganate with concentration 0.02mol dm3
80 cm3 of Sulphuric acid
Method
The method for this titration is the same as before except for the reactants. In this titration the burette needs to be filled with the Potassium Manganate. Once again the mixture of Ethandioate acid and Sodium Ethandioate will be pipetted into the conical flask, however about 20 cm3 of sulphuric acid will need to be added. This is to acidify the sodium ethandioate into ethandioic acid. This mixture will also need to be heated to about 60ºc before titrating with the potassium manganate. No indicator is required; the end point will be when the potassium manganate no longer dissolves, therefore when the solution in the conical flask turns pink.
Health and Safety
The mixture of Ethandioic acid and Sodium Ethandioate, Potassium Manganate and Sodium Hydroxide can cause skin and eye irritations. Therefore Lab coats and safety goggles must be worn at all times while handling these substances.
Analysis
Titration of Ethandioic acid and Sodium Hydroxide
- Number of moles of Sodium Hydroxide:
0.06 x Volume
1000
= A
- Number of moles of Ethandioic acid:
(Using equation for mole ratio)
Moles of Sodium Hydroxide, A
2
= B
Titration of Ethandioic acid and Sodium Ethandioate with Potassium Manganate
- Number of Moles of Potassium Manganate
0.02 x Volume
1000
= X
- Number of Moles of Ethandioate acid:
(Using equation for mole ratio)
Moles of Potassium Manganate, X x 5
2
= Y
Percentage Composition of Ethandioic acid and Sodium Ethandioate
-
Mass of Ethandioic acid present in 25 cm3 in titration with Sodium Hydroxide:
(Mr of Ethandioic acid = 126)
Moles, B x 126
= C
-
Mass of Ethandioic acid present in 200 cm3 in titration with Sodium Hydroxide
Mass, C x 8
=D
-
Mass of Ethandioic acid present in cm3 in titration with Potassium Manganate:
(Mr of Ethandioic acid = 126)
Moles, Y x 126
= Z
-
Mass of Ethandioate acid present in 200 cm3 in titration with Potassium Manganate:
Mass Z x 8
= T
- Percentage of Ethandioic acid present in mixture:
Mass, D
2
= _____ %
- Percentage of Sodium Ethandioate:
(Mass, T – Mass, D)
2
= _____ %
