Preparation and Standardization of 0.1 N Hydrochloric Acid (0.1 N HCl)

Preparation of 0.1 N Hydrochloric Acid (0.1 N HCl)

Take a 100 mL of purified water or water in 1000 mL volumetric flask. Add 8.1774 (Approximately 8.2 mL of 37% Concentrated HCL) carefully. Add 700 mL water. Allow Solution to *cool down to Room Temperature. Make up the volume upto 1000 mL by water.

* Because of Thermodynamic reaction volume may vary, so final volume shall be added after partial addition of volume.

Now,

Grams of compound required = (0.1 N) * (36.4611)* (1 Litre) = 3.6461 g
Volume of concentrated acid required = (3.6461) / (0.375 x 1.189) = 8.1774 ml
Therefore, 8.1774 ml of 37.5% concentrated HCL is required to prepare 0.1 M HCL.

Accurately weigh 0.5 to 1 g of Anhydrous Sodium Carbonate (Na₂CO₃) in suitable dish or crucible and keep dry at 250°C for approximately 4 hr.
After completion of the activity allow to cool in a desiccator.
Accurately weigh 0.22 g of dried Sodium Carbonate (Na₂CO₃) and transfer to 250 mL conical flask. Add 50 mL of water (H₂O), mix well, and allow to dissolve the carbonate.
Add 2 drops of 0.1% solution of methyl red in alcohol as an indicator.
Titrate with HCl Solution filled in Burette accurately.

Na₂CO₃ + 2HCl = 2NaCl + H₂O + CO₂.

The equivalent weight (wt.) of Na₂CO₃ is half its molecular weight (M). This means M/2 g of Na₂CO₃ is equivalent to 1000 ml of 1 N HCl.

Accurately weight 1.0 to 2.0 g of Tris(hydroxymethyl)-aminomethane (THAM or TRIS) ((HOCH₂)₃CNH₂ ) in a suitable dish or crucible and keep for dry at 105°C for approximately 3 to 4 hr.
After completion of activity allow to cool in desiccator.
Accurately weight 0.50 g of dried THAM or TRIS and transfer to 250 mL conical flask. Add 50 mL of Water (H₂O) which is ammonia and Carbon Dioxide free, mix well and allow to dissolve.
Add 2 drops of Bromocresol Green as an indicator.
Titrate with HCl Solution filled in Burette accurately.