VOLUMETRIC ANALYSIS CORE PRACTICAL (chemistry)

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welcome
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VOLUMETRIC ANALYSIS CORE PRACTICAL (chemistry)

• By
• Maruthu pandi .M,\
• Madurai,
• TN,Indian

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1) ESTIMATION OF AMINO ACID (GLYCINE) BY
SORENSONS FORMAL TITRIMETRIC METHOD

• Aim
• To estimate the amount of amino acid (Glycine)
  present in the whole of the given unknown
  solution
• Principle
• Amino acid reacts with excess of formaldehyde to
  give free hydrogen ion and act as acidic
  solution. This acidic solution is titrated
  against standard alkali (Sodium hydroxide) using
  phenolphthalein as indicator.
• Reagents required
• i. Standard oxalic acid solution (0.1 N).
• ii. Sodium hydroxide solution .
• iii. Phenolphthalein as indicator.
• iv. Formaldehyde .
• v. Amino acid (Glycine)

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Procedure

• Titration I
• Standard oxalic acid Vs Sodium hydroxide solution
  
• Weighed accurately 1.576 g of crystalline oxalic
  acid and transfer into a 250 ml of standard flask
  
• then the volume is made up to 250 ml using
  distilled water. Pipette out exactly 20 ml of
  this solution
• into a clean conical flask and two drops of
  phenolphthalein as indicator is added. This is
  titrated against
• the Sodium hydroxide solution taken in the
  burette. The end point is the appearance of pale
  permanent
• pink colour. The titrations are repeated for
  concordant values. From the titre value the
  normality of
• Sodium hydroxide solution is calculated.

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Procedure

• Titration I
• Standard oxalic acid Vs Sodium hydroxide solution
  
• Weighed accurately 1.576 g of crystalline oxalic
  acid and transfer into a 250 ml of standard flask
  
• then the volume is made up to 250 ml using
  distilled water. Pipette out exactly 20 ml of
  this solution
• into a clean conical flask and two drops of
  phenolphthalein as indicator is added. This is
  titrated against
• the Sodium hydroxide solution taken in the
  burette. The end point is the appearance of pale
  permanent
• pink colour. The titrations are repeated for
  concordant values. From the titre value the
  normality of
• Sodium hydroxide solution is calculated.

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Procedure

• Titration III (Blank value)
• Blank Vs Standardized Sodium hydroxide solution
• Pipette out exactly 20 ml of distilled water into
  a clean conical flask to this 5 ml of
  formaldehyde
• and followed by two drops of phenolphthalein as
  indicator is added. The contents are mixed well
  for 5
• minutes. This is titrated against the
  standardized Sodium hydroxide solution taken in
  the burette. The
• end point is the appearance of pale permanent
  pink colour. The titrations are repeated for
  concordant values.

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ESTIMATION OF AMINO ACID (GLYCINE) BY SORENSONS
FORMAL TITRIMETRIC METHOD

1. CALCULATION (Titration I Standard oxalic acid
   Vs Sodium hydroxide)
2. Weight of oxalic acid 1.576 g
3. Volume of Standard oxalic acid solution (V 1)
   20 ml
4. Normality of Standard oxalic acid solution (N1 )
   0.1 N
5. Volume of Sodium hydroxide solution (V2)
   -------- ml
6. Normality of Sodium hydroxide solution (N2) ?
   
7. We know that, V1N1 V2N2
8. N2 V1N1
9. V2
10. N2 20 x 0.1/---------
11. N2 -----------------
12. Normality of Sodium hydroxide solution (N2)
    ---------------------------

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Calculation

• Volume of Sodium hydroxide solution (V 1)
  -------------- ml
• Normality of Sodium hydroxide solution (N1)
  -------------- N
• Volume of amino acid (Glycine) solution (V2) 20
  ml
• Normality of amino acid (Glycine) solution (N2)
  ?
• We know that,
• V1N1 V2N2
• N2 V1N1
• V2
• N2 ----------------
• Normality of amino acid (Glycine) (N2)
  ------------------ N
• Equivalent weight of Glycine - 75
• The amount of amino acid (Glycine) present in the
  whole of the given unknown solution
• Normality of amino acid (Glycine) x
  Equivalent weight of Glycine x 100
• 1000
• ----------------------------- grams

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Test value Blank value

• Test value Blank value will give the actual
  amount of Sodium hydroxide consumed by the amino
  acid solution. From this value the strength of
  amino acid is calculated, and from this strength
  the amino acid present in the whole of the given
  unknown solution is calculated
• Equivalent weight of Glycine 75
• Result
• The amount amino acid (Glycine) present in the
  whole of the given unknown solution is
  ----------------------- grams

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3) ESTIMATION OF SUGAR (GLUCOSE) BY BENEDICTS
TITRIMETRIC METHOD

• Aim
• To estimate the amount of Sugar (Gluose) present
  in the whole of the given unknown solution
• Principle
• When glucose is heated with an alkaline solution
  of copper (Cu2) ions, the copper (Cu2) ions is
  reduced to cupric (Cu) ion, which is
  precipitated as copper oxide CuO2. This is the
  basic for the estimation of reducing sugar.
• Reagent required
• Benedicts quantitative Reagent
• Crystalline copper sulphate 18 grams,
  anhydrous sodium carbonate 200 grams, potassium
  thio cyanate 125 grams, sodium nitrite 200
  grams are added to 250 ml of distilled water and
  dissolved with the aid of heat. The contents are
  finally made up to 800 ml using distilled water.
  
• Standard glucose solution
• Weighed accurately 250 mg of Glucose and transfer
  into a 250 ml of standard flask then the volume
  is made up to 250 ml using distilled water.
  (concentration 1 mg/1 ml)

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Procedure

• Titration I
• Standard Glucose solution Vs Benedicts
  quantitative Reagent
• Pipette out exactly 5 ml of Benedicts
  quantitative reagent into a clean conical flask.
  To this add 1 gram of sodium carbonate. The
  contents are mixed well and heated in boiling
  water bath till the first bubble
• appearance. This is titrated against the Standard
  Glucose solution taken in the burette. The end
  point is the disappearance of blue colour. The
  titrations are repeated for concordant values
• Precaution
• i. Excess amount Sodium carbonate will cause
  frothing ii. Benedicts quantitative Reagent is
  kept at boiling throughout in the titration iii.
  Porcelain bits are added to prevent bumping

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Procedure

• Titration II
• Unknown Glucose Vs Benedicts Reagent
• The given unknown Glucose solution is made up to
  100 ml standard flask using distilled water.
• The burette is rinsed with unknown Glucose
  solution and filled with the same unknown Glucose
  
• solution. Pipette out exactly 5 ml of Benedicts
  quantitative Reagent into a clean conical flask
  to this
• 1gram of sodium carbonate added. The contents are
  mixed well and heated till the first bubble
• appearance. This is titrated against the unknown
  Glucose solution taken in the burette. The end
  point is
• the disappearance of blue colour. The titrations
  are repeated for concordant values.

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calculation

• calculation
• X - Volume of standard Glucose
• Y - Volume of unknown Glucose
• ie. --------------------- ml of standard Glucose
• --------------------- ml of unknown Glucose
• 100 ml of unknown solution contain X
• Y
• -------------------- mg
• Result
• The amount of Sugar (Glucose) present in the
  whole of the given unknown
• Solution ------------------------ grams

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3)ESTIMATION OF ASCORBIC ACID USING 2, 6 DICHLORO
PHENOL INDOPHENOL

• Aim
• To estimate the amount of ascorbic acid present
  in the whole of the given unknown solution
• Principle
• Ascorbic acid is oxidized by the colourD dye 2,
  6 Dichloro phenol indophenol to dehydro
• ascorbic acid. At the same time the dye is
  reduced to colourless compound, so that, the end
  point of the
• reaction can be easily determined.

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Reagent required

• 2, 6 Dichloro phenol indophenols
• Dissolve 42 grams of Sodium bi carbonate and 52
  grams of Dichloro phenol indophenols in 50 ml of
  distilled water and finally dilute to 250 ml
  using distilled water.
• Stock standard ascorbic acid solution
• 100 mg of ascorbic acid is weighed exactly and
  carefully transfer in to 100 ml standard flask
  and made up to 100 ml using 0.6 oxalic acid.
• Working standard ascorbic acid solution
• 10 ml of Stock standard ascorbic acid solution
  is pipette out in to a 100 ml standard flask and
  made up to 100 ml using 0.6 oxalic acid.

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Procedure

• Titration I
• Standard Ascorbic acid Vs Dye
• Pipette out exactly 10 ml of working standard
  ascorbic acid solution into a clean conical flask
  and it is titrated against the dye taken in the
  burette. The end point is the appearance of pale
  permanent pink colour. The titrations are
  repeated for concordant values.

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Procedure

• Titration II
• Unknown Ascorbic acid Vs Dye
• The given unknown ascorbic acid solution is made
  up to 100 ml standard flask using 0.6 oxalic
  acid. Pipette out exactly 10 ml of this unknown
  ascorbic acid solution into a clean conical flask
  and it is titrated against the dye taken in the
  burette. The end point is the appearance of pale
  permanent pink colour. The titrations are
  repeated for concordant values.

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calculation

• Working standard ascorbic acid 10 mg ascorbic
  acid/100 ml of 0.6 oxalic acid
• Concentration 0.1 mg/1 ml
• Ie. 1 ml of standard contains 0.1 mg of ascorbic
  acid
• 10 ml standard contains 0.1 mg x 10 1 mg of
  ascorbic acid
• 10 ml standard ascorbic acid contains
  -------------------------- ml of Dye
• Ie. 1 mg of ascorbic acid consumes
  ---------------------------- ml of Dye

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• But X of ascorbic acid consumes
  ------------------------ ml of Dye
• The amount of ascorbic acid present in the 100 ml
  of unknown solution
• -------------------- mg
• The amount of ascorbic acid present in the whole
  of the given unknown solution
• ------------------ mg x 10
• ------------------- mg
• Result
• The amount of ascorbic acid present in the whole
  of the given unknown Solution -------------------
  ----- mg

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4) DETERMINATION OF ACID NO OF FAT

• Aim
• To estimate the amount of Acid no of the given
  Fat
• Principle
• During storage of fat become rancid. As a result
  the peroxide formation of the double bond by
  atmospheric oxygen and or hydrolyzed by micro
  organism with liberation of free fatty acids. The
  amount of acid present gives the indication of
  age and quality of the fat.
• Acid value is the number of milligrams of KOH
  required to neutralize the free fatty acids in
  one gram of a
• fat or oil. It is a measure of free fatty acid
  contents in a fat or oil.
• Reagents required
• i. Fat ii. Fat solvent iii. Standard 0.1 N oxalic
  acid iv. Potassium hydroxide solution v.
  Phenolphthalein as indicator. vi. Methanol /
  Ethanol

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Procedure

• Titration I
• Standard oxalic acid Vs Potassium hydroxide
  solution
• Weigh accurately 1.575 g of oxalic acid and
  transfer into a 250 ml of standard flask then the
  volume is made up to 250 ml using distilled
  water. Pipette out exactly 20 ml of this solution
  into a clean conical flask and two drops of
  phenolphthalein as indicator is added.
• This is titrated against the Potassium hydroxide
  solution taken in the burette. The end point is
  the appearance of pale permanent pink colour. The
  titrations are repeated for concordant values.
  From the titre value the normality of Potassium
  hydroxide solution is calculated.

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Procedure

• Titration II
• Test Value Weigh about one gram of edible oil and
  carefully transfer in to a clean dry conical
  flask. Then 50 ml of alcohol is added followed by
  two drops of phenolphthalein as indicator is
  added. The contents are mixed well for 20
  minutes.
• This is titrated against the standardized
  Potassium hydroxide solution taken in the
  burette. The end point is the appearance of pale
  permanent pink colour and persisting up to 20
  30 seconds.

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Procedure

• Titration III
• Blank Value
• 50 ml of alcohol is taken in a conical flask and
  three drops of phenolphthalein as indicator is
  added. The contents are mixed well. This is
  titrated against the standardized Potassium
  hydroxide solution taken in the burette. The end
  point is the appearance of pale permanent pink
  colour and persisting up to 20 30 seconds.

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Titration I

• Volume of Standard oxalic acid solution (V 1)
  20 ml
• Normality of Standard oxalic acid solution (N1 )
  0.1 N
• Volume of Potassium hydroxide solution (V2)
  -------- ml
• Normality of Potassium hydroxide solution (N2)
  ?
• We know that,
• V1N1 V2N2
• N2 V1N1
• V2
• N2 20 x 0.1/---------
• N2 -----------------
• Normality of Potassium hydroxide solution (N2)
  --------------------------- N

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• 100 ml of 1 N Potassium hydroxide contain 56
  grams of Potassium hydroxide
• X 56 x Strength of Potassium hydroxide x
  Test value Blank value 1000
• --------------------- grams
• Acid no of Fat ---------------------- grams x
  1000
• Weight of Oil -----------------------------
  Acid no of Fat(Oil)
• Result
• Acid No of the given Fat ----------------------
  --------

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5)DETERMINATION OF IODINE NO OF FAT

• Aim
• To estimate the amount of Iodine no of the given
  Fat
• Principle
• Iodine no of fat is defined as the no of grams
  of iodine absorbed by 100 gram of fat or oil. It
  is a measure of degree unsaturation of the fatty
  acids in a fat or oil. Unsaturated fatty acids,
  either free or combined in lipids react with
  halogens like bromine and iodine which get
  decolorized. These halogens add at the carbon
  carbon double bond.
• Hanes method is used for the determination of
  Iodine number. About 1 gram of the fat is taken
  in a well cleaned dry iodine flask. To this 20 ml
  of chloroform is added to dissolve the fat. The
  contents are
• shaken well and kept for 30 minutes. Then 20 ml
  of potassium iodide is added to liberate the
  iodine and it is titrated against standard sodium
  thio cyanate solution. From this titration iodine
  number of fat is calculated.

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Reagents required

• i. Hanes solution ii. Fat iii. Standard 0.1 N
  potassium dichromate solution iv. Sodium thio
  cyanate solution v. 10 potassium iodide vi. 1
  Starch vii. Chloroform
• Preparation of Hanes solution
• 3.3 grams of iodine is dissolved in 200 ml of
  acetic acid by constant shaking and heating. It
  is cooled to
• room temperature, to this 50 ml of glacial acetic
  acid containing 0.75 grams of Bromine is added
  and
• mixed well and stored in brown bottle.

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Procedure

• Titration I
• Standard potassium dichromate solution Vs Sodium
  thio cyanate solution
• Weighed accurately 1.225 g of potassium
  dichromate solution and transfer into a 250 ml of
  standard flask then the volume is made up to 250
  ml using distilled water. Pipette out exactly 20
  ml of this solution into a clean conical flask
  to this 5 ml of Conc. Hydrochloric acid is added,
  followed by 10 ml of 10 potassium iodide is
  added. This contents are mixed well and titrated
  against the Sodium thio cyanate solution taken
  in the burette, the titration is continued until
  a pale brown colour is appears.
• At the time 1 ml of 1 Starch solution is added.
  And the titration is continued till to get the
  end point appearance of emerald green colour, it
  is the end point. The titrations are repeated for
  concordant values. From the titre value the
  normality of Sodium thio cyanate solution is
  calculated.

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Procedure

• Titration II
• Determination of iodine no of fat (Test value)
  Weigh about one gram of edible oil and carefully
  transfer in to a clean dry iodine flask. Then 20
  ml of Chloroform is added, the contents are mixed
  well to dissolve the oil. To this 20 ml of Hanes
  solution is added, shaken well and kept in dark
  for 30 minutes with occasional shaking. Then the
  flask is taken out to this 20 ml of 10
  potassium iodide is added to liberate iodine.
  Except the iodine that is absorbed by the oil.
• To this mixture 100 ml of distilled water is
  added, so the liberated iodine is nicely
  disturbed in the solvent then it is titrated
  against the Sodium thio cyanate solution taken
  in the burette, the titration is continued until
  a pale brown colour is appears. At the time 1 ml
  of 1 Starch solution is added. And the
  titration is continued till to get the end point
  disappearance of blue colour it is the end

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Titration I

• Volume of Standard potassium dichromate solution
  (V 1) 20 ml
• Normality of Standard potassium dichromate
  solution (N1) 0.1 N
• Volume of Sodium thio cyanate solution (V2)
  -------- ml
• Normality of Sodium thio cyanate solution (N2)
  ?
• We know that,
• V1N1 V2N2
• N2 V1N1
• V2
• N2 20 x 0.1/---------
• N2 -----------------
• Normality of Sodium thio cyanate solution (N2)
  --------------------------- N

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• Blank value
• Blank value is also done without oil
• Equivalent weight of iodine 127
• Weight of the oil
• Weight of the weighing bottle Oil
• Weight of the weighing bottle ( - )
• Weight of the Oil transferred
• Blank value - Test value -------------------
  - ml
• Determination of iodine no of fat
• Equivalent weight of iodine x Blank value -
  Test value x Normality of Sodium thio cyanate
  solution x 100
• 1000 x Weight of the Oil
• ---------------------------------- Iodine no of
  fat (oil)

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Result Iodine No of the given Fat (Oil)
------------------------------
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By Maruthu pandi .M,\ Madurai, TN,Indian
Thanking you