Preparation and standardization of 0.1 M Hydrochloric acid

1.0                                     SCOPE:

                       The procedure is applicable to preparation and standardization of 0.1 M Hydrochloric

                       acid.

2.0                                     APPARATUS:

2.1               50ml Burette (0.1ml graduated)

2.2               1000ml volumetric flask

2.3               1 ml & 2ml Pipettes

2.4               100ml measuring cylinder

2.5               Analytical Balance.

                   (Use Class ‘A’ glassware)

3.0                                     REAGENTS:

3.1               Hydrochloric acid   (Analytical Grade)

3.2               Sodium Carbonate (Primary Standard).

3.3               Methyl Red Indicator

3.4               0.1M Sodium Hydroxide.

3.5                Ethanol (95%).

3.6                Water.

4.0                               PROCEDURE:

 4.1              Preparation of Solution:

 4.1.1           Dilute 8.5 ml of Hydrochloric Acid in sufficient water to produce 1000 ml.

4.2               Preparation of Methyl Red Solution:

4.2.1           Weigh accurately 50 mg of methyl red transfer into 100 ml volumetric flask. Dissolve

    in a mixture of 1.86 ml of 0.1 M sodium hydroxide and 50 ml of ethanol (95%). After

     solution is affected, add sufficient water to produce 100 ml and mix.

                      Note: If prepared solution is available same to be used upto validity.

                                                    (OR)

   If ready made solution is available, shall be used.

 4.3             Standardization :                                       Molarity Limit : + 10% (0.0900 to 0.1100)

   4.3.1          Weigh accurately about 0.15 g of anhydrous sodium carbonate, previously dried at  

                     about 270°C for 1 hour. Dissolve it in 100 ml of water and add 0.1 ml of methyl red

                     solution. Add the acid slowly from the burette, with constant stirring, until the solution

                     become faintly pink. Heat the solution to boiling, cool and continue the titration. Heat                  

                     again to boiling and titrate further as necessary until the faint pink colour is no longer

affected by continued boiling.

1 ml of 0.1M hydrochloric acid is equivalent to 0.005299 g of Na₂CO₃.

Calculation:

Molarity of 0.1 M Hydrochloric Acid

        Wt. of Na₂CO₃ taken in gm x 0.1

= -----------------------------------------------------

     0.005299 x Titer volume of 0.1 M HCl

                    Standardization should be carried out in triplicate.

                    Report the triplicate mean value.

                     The % RSD of triplicate mean value should not be more than 2.0.

5                                        STORAGE:

5.1               Store at Below 25°c.

6                                  SHELF LIFE:

6.1               Shelf life of the above solution shall be one month from the date of preparation.

6.2               Restandaridize the above solution once in 7 days.

                      NOTE: Discard the volumetric solution whenever sedimentation, crystallization or

                                    fiber particles observed in the reagent bottle.

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