How to Prepare Standard Volumetric Solution as per USP

PREPARATION OF STANDARD 1(N) SODIUM HYDROXIDE (NaOH) SOLUTION.

Rapidly weigh out about 10 gm of sodium hydroxide in a small beaker and dissolve it in 50 ml of distilled water. Pour the content of the beaker into a 250-ml volumetric flask and make up the volume up to the mark with distilled water. This is approximately 1(N) NaOH solution.

STANDARDIZATION OF 1(N) SODIUM HYDROXIDE SOLUTION.

Transfer 10 ml NaOH solution by a pipette to a 100-ml volumetric flask and make up the volume up to the mark with distilled water. Take this solution in a burette.
Pipette out 25 ml of standard 0.1(N) potassium hydrogen phthalate solution and transfer it into a 100-ml conical flask. Titrate with the NaOH solution using phenolphthalein or thymol blue as an indicator.
Normality is readily computed from the relation, Va Na  = Vb Nb
Where Va and Na are the volume (in ml) taken and normality of the potassium hydrogen phthalate solution respectively,  Vb is the volume of NaOH solution in ml required for neutralization and Nb is the (unknown) normality of NaOH solution.
 
Strength of original NaOH solution  =  10 x 25 x 0.1 =    25
                                                                         V              Vb

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PREPARATION OF STANDARD 0.5(N) SODIUM HYDROXIDE (NaOH) SOLUTION.

Rapidly weigh out about 5 gm of sodium hydroxide in a small beaker and dissolve it in 50 ml of distilled water. Pour the content of the beaker into a 250-ml volumetric flask and make up the volume up to the mark with distilled water

STANDARDIZATION OF 1(N) SODIUM HYDROXIDE SOLUTION.

Strength of original NaOH solution  =  10 x 25 x 0.1      =    25

                                                                       V                     Vb

 PREPARATION OF STANDARD 0.1 (N) OXALIC ACID SOLUTIONS

Weigh out accurately 0.6303 gm of oxalic acid (H2C2O4. 2H2O) and quantitatively transfer it to a 100-ml volumetric flask. Make up the volume up to the mark with distilled water and shake to make a standard 0.1 (N) oxalic acid solution.
Keep it in the volumetric flask under stoppered conditions.
 
This is a standard 0.1(N) oxalic acid solution.
 
Weigh out accurately 0.6303 gm of oxalic acid (H2C2O4. 2H2O) and quantitatively transfer to a 100-ml volumetric flask. Make up the volume up to the mark with distilled water and shake to make a standard 0.1 (N) oxalic acid solution.
Keep it in the volumetric flask under stoppered conditions.
This is a standard 0.1(N) oxalic acid solution.

PREPARATION OF STANDARD 0.1 (N) POTASSIUM HYDROGEN PHTHALATE SOLUTION

 Weigh out accurately 2.04 gms of potassium hydrogen phthalate and quantitatively transfer to a 100-ml volumetric flask. Make up the volume up to the mark with distilled water and shake well to make a standard 0.1 (N) potassium hydrogen phthalate solution. Keep it in the volumetric flask under stoppered conditions.

PREPARATION OF STANDARD 1(N) HYDROCHLORIC ACID SOLUTION

Transfer by means of a measuring cylinder 45 ml of concentrated hydrochloric acid into a 500 ml volumetric flask containing about 300 ml of distilled water. Cool and fill up to the mark with distilled water. This will give a solution of approximately 1(N) HCl.

Pipette out 25 ml of HCl solution into a 250 ml conical flask and add 2 drops of methyl red or methyl orange indicator. Titrate with standard 1(N) sodium hydroxide (NaOH) solution. Continue the addition until the color becomes faint yellow or orange for methyl red and methyl orange respectively.
 
Normality of HCl acid solution   =   Vol. in ml of standard NaOH solution x Normality of NaOH
                                                                  Vol. in ml of hydrochloric acid solution

PREPARATION OF STANDARD 0.1 (N) HYDROCHLORIC ACID SOLUTIONS

Transfer by means of a graduated pipette 4.5 ml of concentrated hydrochloric acid (HCl) into a 500 ml volumetric flask containing 300 ml of water; Cool and dilute to 500 ml. This will give a solution of approximately 0.1(N) hydrochloric acid.
 

STANDARDIZATION:


Pipette out 25 ml of the acid solution to a 250 ml conical flask and add 2 drops of methyl red or methyl orange indicator. Titrate with standard 0.1 (N) sodium hydroxide solutions taken in a burette till the color becomes faint yellow or orange for methyl red and methyl orange respectively.
 
Normality of HCl acid solution   =  Vol. in ml of standard NaOH solution x Normality of NaOH
                                                                Vol. in ml of hydrochloric acid solution
 

PREPRATION OF 2(N) SULFURIC ACID SOLUTION

Take distilled water in a 500 ml glass beaker and slowly add 28 ml concentrated sulfuric acid (H2SO4) with stirring. Store this approximately 2(N) H2SOsolution in a stoppered reagent bottle.

PREPRATION OF STANDARD 1(N) SULFURIC ACID SOLUTION 

Transfer by means of a graduated pipette 14 ml of concentrated sulfuric acid (H2SO4) into a 500 ml volumetric flask containing about 200 ml of distilled water. Cool and dilute to 500 ml with distilled water. This is a solution of approximately 1(N) sulfuric acid.
 
STANDARDIZATION:
                                           
Pipette out 25 ml of the acid solution into a 250 ml conical flask and add 2 drops of methyl red or methyl orange indicator. Titrate with standard 1(N) sodium hydroxide (NaOH) solution until the color becomes faint yellow or orange for methyl red and methyl orange respectively.
 
Normality of sulfuric acid solution =   Vol. in ml of standard Noah solution x Normality of NaOH
                                                                          Vol. in ml of sulfuric acid solution taken.

Buffer solution in chemistry and Types of buffer Solutions

PREPRATION OF STANDARD 0.1 (N) SULFURIC ACID SOLUTIONS

Transfer by means of a graduated pipette 1.4 ml of concentrated sulfuric acid H2SO4 into a 500-ml volumetric flask containing about 200 ml of distilled water. Cool and dilute to 500ml with distilled water. This is a solution of approximately 0.1(N). Sulfuric acid.
 
STANDARDIZATION:
                                           
Pipette out 25 ml of the acid solution into a 250 ml conical flask and add 2 drops of methyl red or methyl orange indicator. Titrate with standard 0.1 (N) sodium hydroxide solutions till the color becomes faint yellow or orange for methyl red and methyl orange respectively.
 
Normality of sulfuric acid solution = Vol. in ml of standard NaOH solution x Normality of NaOH
                                                       Vol. in ml of sulfuric acid solution taken.

 

PREPARATION OF STANDARD 1(N) POTASSIUM PERMANGANATE (KMnO4) SOLUTION.

Take 1 liter of distilled water in a 2-lit glass beaker. Weigh out 32.0-32.5gms. Potassium Permanganate (KMnO4 ) on a watch glass and add to the distilled water in the beaker. Heat the beaker on a hot plate and gently boil its content for 15-30 minutes till it dissolves in water.
Cool the solution to room temperature. Filter through glass wool or sintered glass crucible and store in a stoppered dark brown bottle. This is approx. 1(N) KMnO4 solution
 

STANDARDIZATION:

Take 10 ml of the above KMnO4 solution in a 100-ml volumetric flask with a pipette and make up the volume up to the mark with distilled water. Transfer 10 ml standard 0.1 (N) oxalic acid solution by a volumetric pipette to a conical flask. Add 60 ml 2(N) H2SO4 solution & titrate rapidly with the diluted KMnO4 solution taken in a burette until the first pink color appears throughout the solution. Allow standing for some time. If the solution becomes colorless, warm it to 50-60 oC and continue the titration to a permanent faint pink color. Successive titrations should agree within 0.1 ml
 
Normality is readily computed from the relation,     Va  Na  =  Vb  Nb
 
Where Va and Na are the volumes taken in ml and normality of oxalic acid solution respectively, Vb is the volume of KMnO4 solution in ml and Nb is the (unknown) normality of KmnO4 solution.
 
Strength of original KMnO4 solution.   = 10 x 10 x 0.1     =     10
                                                                             Vb                     V
b

PREPARATION OF STANDARD 1(M) Sodium Sulphite (Na2SO3) SOLUTION

Weigh out accurately 31.5 gm of Sodium Sulphite (Na2SO3) and quantitatively transfer to a 250ml volumetric flask.    Make up the volume up to the mark with distilled water and shake to make a standard 1 (M) Sodium Sulphite solution.
     
Keep it in the volumetric flask under stoppered conditions. This is a standard 1 (M) Sodium Sulphite solution.

PREPARATION OF 0.1 N OF AQ.KOH SOLUTION

Dissolve 2.8 gms of KOH flakes (potash alkali) in 200 ml of Distilled water in a 500 ml volumetric flask. After complete dissolution makeup up to mark with distilled water.

STANDARDIZATION OF KOH SOLUTION:

Make a standard 0.1 N Oxalic Acid solution and take 25ml of this solution with the help of the pipette in the conical flask and titrate against KOH solution by using Phenolphthalein as an indicator.

Endpoint – Colorless to violet.
 
 
N1V1 = N2V2
 
N1      = N2V2
               V1
 
Where
 
N1 = Normality of KOH
V1 = Volume of KOH
N2 = Normality of Oxalic Acid
V2 = Volume of Oxalic Acid 

PREPARATION OF 0.1 N OF ALCOHOLIC KOH SOLUTION

Dissolve 2.8 gms of KOH flakes (potash alkali) in 250ml of methanol in a 500ml volumetric flask. After complete dissolution makeup up to the mark with methanol.

STANDARDIZATION OF KOH SOLUTION:

Make a standard 0.1 N Oxalic Acid solution and take 25ml of this solution with the help of the pipette in the conical flask and titrate against KOH solution by using Phenolphthalein as an indicator. 
Endpoint – Colorless to violet.
 
 
N1V1 = N2V2
 
N1      = N2V2
               V1
 
Where
 
N1 = Normality of KOH
V1 = Volume of KOH
N2 = Normality of Oxalic Acid
V2 = Volume of Oxalic Acid
 

PREPARATION OF STANDARD 0.1 N DIBUTYL-AMINE SOLUTION.

Weigh accurately 12.925gm.of Dibutyl amine (LR) in a 1000ml volumetric flask.
Make up the volume up to the mark by shaking with Toluene (LR).
Keep it in the volumetric flask under stoppered conditions.
This is the standard 0.1N Dibutylamine solution.

PREPARATION OF STANDARD 0.1 N SODIUM THIOSULPHATE

Weigh accurately 25gm.of Sodium Thiosulphate in a 1000ml volumetric flask. 
Make up the volume up to the mark by shaking it with hot distilled water.
Keep it in the volumetric flask under stopper conditions in a cool & dirt place.
This is the standard 0.1N Sod. Thiosulphate solution.
To improve the life of 0.1N Sod. In thiosulphate solution add 0.1gm of Na2CO3.

PREPARATION OF 0.5 N OF AQ.KOH SOLUTION

Dissolve 14 gm of KOH Flasks (Potash Alkali) in 200 ml of distilled water in a 500 ml volumetric flask. After complete dissolution makes up to mark with distilled water.

STANDARDIZATION OF KOH SOLUTION

Transfer 10ml KOH solution by a pipette to a 100 ml volumetric flask and make up the volume up to the mark with distilled water. Take this solution in a burette.
Pipette out 25ml of standard 0.1N oxalic acid solution and transfer into a 100ml conical flask. Titrate with the KOH solution using Phenolphthalein as an indicator.
 
End Point              -               Colourless to Voilet
 
 
Normality of original in KOH solution           =          10x25x0.1= 25
                                                                                                        Vb         
Vb         =        Volume of KOH Solution

 

PREPARATION OF 0.5 N OF ALCOHOLIC KOH SOLUTION

Dissolve 14 gm of KOH Flasks (Potash Alkali) in 200 ml of distilled water in a 500 ml volumetric flask. After complete dissolution makes up to mark with distilled water.
 

STANDARDIZATION OF KOH SOLUTION
 
Transfer 10 ml KOH solution by a pipette to a 100 ml volumetric flask and make up the volume up to the mark with distilled water. Take this solution in a burette.
Pipette out 25 ml of standard 0.1N oxalic acid solution and transfer it into a 100 ml conical flask. Titrate with the KOH solution using Phenolphthalein as an indicator.
 
End Point              -               Colorless to Violet
 
 
Normality of original in KOH solution           =          10x25x0.1= 25
                                                                                                        Vb          
 
Vb         =        Volume of KOH Solution

PREPARATION OF 0.1 N OF HYDROBROMIC ACID SOLUTION

Dissolve 8.0 of Hydrobromic acid and 200 ml of glacial acetic acid in a 500 ml volumetric flask. After complete dissolution makes up to mark with glacial acetic acid.

STANDARDIZATION OF HBR SOLUTION

Analytically weigh 0.4±0.005 gm of potassium acid phthalate into a 100 ml Erlenmeyer flask. Weight a duplicate into a second flask.
 
Add 10 ml of glacial acetic acid to each sample and heat gently to dissolve the phthalate.
Titrate the sample using approximately 12.5 ml of the 0.1 n HBr solution to a green color using two to three drops of methyl violet indicator.
The solution will change from purple to dark, then light, and blue until obtaining the green color. The final color change is obvious.  
 
 
End Point  -  blue until obtaining the green color
 
Normality of original in HBr solution         =          Weight of Pht X 1000
                                     204.2 X ml of HBr                

 


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