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Chemistry Lab Experiment 2
Reaction of Potassium Manganate
with Oxalic acid
Mashiat and
Kausar
Purpose of experiment
• To carry out oxidation of hydrated Oxalic acid
(Ethanedioic acid) (H2C2O4.xH2O) by Potassium
manga...
PROCEDURE
Reagents
FA1: 5.00 dm-3 of H2C2O4.xH2O
FA2: 2.37 dm-3 of KMnO4
1.00 moldm-3 H2SO4
40 cm-3 distilled water
Apparatus used
Burette
Beaker
Pipette
Bunsen burner
Thermometer
Conical flask
Measuring cylinder
Method
1. Burette is filled with purple KMnO4
solution.
2. 25.0 cm3 of H2C2O4.xH2O pipetted
into conical flask.
3. 25 cm3 ...
Results & Observation
1) A strong pungent smell was released when the acidified
solution was heated using Bunsen burner.
2) On reaching end-poin...
Conclusion
• Volume of FA2 used with 25.0 cm3 of FA1:
27.00 cm3
• Moles of KMnO4 used: 0.0004 mol
• Moles of Oxalic acid r...
What I learnt
• Potassium permanganate is a strong oxidizing agent.
• Excess dilute H2SO4 is needed, otherwise it forms
br...
Safety Precautions
• The upper meniscus should be used for burette
readings of colored solutions (KMnO4) as the lower
meniscus isn’t clearly ...
Real-life Applications of Oxalate
• Reducing agent for development of photographic
films.
• Bleaching agent for wood and stone. Wood turns
grey when exposed...
Critical-thinking question
Why is dilute H2SO4 added in KMnO4 titrations
instead of HCl or HBr and HNO3?
Ans: Potassium manganate(VII) can't be used
in titrations in the presence of ions like
chloride or bromide as they consume...
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Chemistry lab experiment 2 - titration of Potassium permanganate with Oxalic acid

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Chemistry lab experiment 2

  1. 1. Chemistry Lab Experiment 2 Reaction of Potassium Manganate with Oxalic acid Mashiat and Kausar
  2. 2. Purpose of experiment • To carry out oxidation of hydrated Oxalic acid (Ethanedioic acid) (H2C2O4.xH2O) by Potassium manganate (VII) (KMnO4) in the presence of acid by titration. • To determine the value of x in H2C2O4.xH2O 2MnO4- (aq) + 5H2C2O4 (aq) + 6H+ (aq) 2Mn2+ (aq) + 10CO2(g) + 8H2O(l)
  3. 3. PROCEDURE
  4. 4. Reagents FA1: 5.00 dm-3 of H2C2O4.xH2O FA2: 2.37 dm-3 of KMnO4 1.00 moldm-3 H2SO4 40 cm-3 distilled water
  5. 5. Apparatus used Burette Beaker Pipette Bunsen burner Thermometer Conical flask Measuring cylinder
  6. 6. Method 1. Burette is filled with purple KMnO4 solution. 2. 25.0 cm3 of H2C2O4.xH2O pipetted into conical flask. 3. 25 cm3 of 1.00 moldm-3 of H2S04 poured using measuring cylinder. 4. 40 cm3 distilled water added using measuring cylinder. 5. The flask is heated using Bunsen burner and temperature observed on thermometer till a little over 65◦C. 6. Flask placed under burette and titration carried out. 7. Flask is swirled continuously until end-point reached.
  7. 7. Results & Observation
  8. 8. 1) A strong pungent smell was released when the acidified solution was heated using Bunsen burner. 2) On reaching end-point, the color of the solution turned from colorless to a permanent pale pink completing the oxidation of Oxalic acid. Hence, no indicator is required as KMnO4 acts as an indicator itself.
  9. 9. Conclusion • Volume of FA2 used with 25.0 cm3 of FA1: 27.00 cm3 • Moles of KMnO4 used: 0.0004 mol • Moles of Oxalic acid reacted: 0.001 mol • Value of x in C2H2O4.xH2O: 1.95 mol
  10. 10. What I learnt • Potassium permanganate is a strong oxidizing agent. • Excess dilute H2SO4 is needed, otherwise it forms brown ppt. of hydrated manganese dioxide, interfering with obtaining the correct end-point. • The oxidation reaction is slow in room temperature, so heating the acidified solution is required to speed up the rate. Heating also releases carbon dioxide that helps the reaction to be completed.
  11. 11. Safety Precautions
  12. 12. • The upper meniscus should be used for burette readings of colored solutions (KMnO4) as the lower meniscus isn’t clearly visible. • Handle flask carefully while heating. Hold the neck of flask using folded paper towel if it’s too hot to hold safely. • Wear gloves while heating and prevent skin contact with Oxalic acid as it’s corrosive. • Potassium permanganate decomposes in bright light, and so cannot be exposed in these conditions for long.
  13. 13. Real-life Applications of Oxalate
  14. 14. • Reducing agent for development of photographic films. • Bleaching agent for wood and stone. Wood turns grey when exposed to weather elements. When Oxalic acid is added to it, the natural color of wood is retained. • Removing stains and rust. Oxalic acid is a gentle stain remover that effectively gets rid of stains without wearing the base away. • Wastewater treatment as Oxalic acid can effectively remove Calcium from wastewater.
  15. 15. Critical-thinking question Why is dilute H2SO4 added in KMnO4 titrations instead of HCl or HBr and HNO3?
  16. 16. Ans: Potassium manganate(VII) can't be used in titrations in the presence of ions like chloride or bromide as they consume some KMnO4 and liberate Cl2 and Br2 , while HNO3 is a stronger oxidizing agent than KMnO4 .
  • PrafulRawal1

    Aug. 26, 2019
  • GabrielMzelela

    May. 11, 2018
  • NikitaNegi10

    Sep. 26, 2016

Chemistry lab experiment 2 - titration of Potassium permanganate with Oxalic acid

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