HYDROCHLORIC ACID 0.1 N



                 Preparation               

Take 8.3 mL of concentrated hydrochloric acid (HCl, sp gr 1.19) into a 1000-ml volumetric flask.Dilute to the mark with water, mix well, and store in a tightly closed glass container.



I. Standardization with Sodium Carbonate

Take 0.5 oto 1 g of primary standard anhydrouso sdium carbonate (Na2CO3) to a suitable dish or crucible, and dry at 250°C for 4 h. Cool in a desiccator.

Weight accurately 0.22 g of the dried Na2CO3, and transfer to a 250-mL conical flask. Add 50 mL of water, swirl to dissolve the carbonate, and add 2 drops of a 0.1 % solution of methyl red in alcohol. Titrate with the HCl solution.
Initial point color.    End point color



              Calculation                

Normality of the Hcl solution(N), as
follows:
 N = A /0.053*B

Where
A - gram of Na2CO3 used,
B - used ml of Hcl solution in titrition.

Ex-
0.2203 gm of Na2CO3
41.7 ml used of Hcl solution.

Normality of the Hcl= 0.2203/0.053*41.7= 0.0997 N


                Stability                

Re-standardize monthly.



II. Standardization with Tris(Hydroxymethyl)- Amimethane

Take 1 to 2 g of primary standard tris(hydroxymethyl)aminomethane[(HOCH2)3CNH2] to a suitable dish or crucible, and dry in a vacuum at 70°C for 24 h. Cool in a desiccator.
weigh accurately 0.40 g of the dried tris(hydroxymethyl)aminomethane, and transferto a 250-mL conical flask. Dissolve in 50 mL of ammonia- and carbon dioxide-free water, and titrate with the HCl solution to a pH of 4.70 using a suitable pH meter.

              Calculation                

Normality of the Hcl solution(N), as
follows:
 N = A /0.1211*B

Where
A - gram of Tris(Hydroxymethyl)- Amimethane used,
B - used ml of Hcl solution in titrition.

Ex-
0.4002 gm of Tris(Hydroxymethyl)- Amimethane
33.1 ml used of Hcl solution.

Normality of the Hcl= 0.4002/0.1211*33.1= 0.0998N


                  Stability                       

Re-standardize monthly.




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