Testing Soda Ash & Hydrogen Peroxide

Testing Soda Ash & Hydrogen Peroxide

In Textile Processing the following materials are considered to be basic chemicals or bulk chemicals used in processing. The quality of each product whether basic  or auxiliary chemical would certainly affect the final quality of textile processing. So a good dye-house should have a continuous quality monitoring procedure like one shown below.  As and when a new product or chemical enters your dye-house, its quality should be compared with the previous supply without fail.

Soda Ash:

Weigh accurately 1 gram of Soda ash and dissolve in 50ml of distilled water. Titrate this slowly with 1.0N HCl, using methyl orange as indicator.

Total alkalinity as Na2CO3.% by weight = 5.3 x V x 1 / Wt where 'V' is the volume of HCl consumed and 'wt' is the exact weight of soda ash taken for titration.

Repeat the above titration for 3 times, tabulate and take the average reading as the % concentration of Soda ash as Sodium carbonate.

Hydrogen Peroxide:

Take 10ml of Hydrogen Peroxide solution and dilute it to 500ml using distilled water. From this diluted solution of Hydrogen peroxide take 10ml and add 20ml of 1.0N H2SO4.. Titrate against 0.1N KMNO4 (potassium permanganate). The end point is the appearance of light pink color. Repeat this titration 3 times and tabulate the readings. Find out the average titration value (V).

[Hope the reader would be aware of the volumetric titration principles. Titrating two solution of standard known strength and unknown strength, one can easily find out the strength of the other. The simple formulae used for this purpose is;

                                                         V₁N₁ = V₂N₂ 

_{where V1 = Volume of Standard Solution, N1 = Normality of Standard solution, V2=- Volume of unknown solution, N2 = Normality of unknown solution.}

_{Concentration of the unknown solution in grams / liter = Normality of unknown solution x Equivalent weight of the substance.]}

_{In the above example, if V is the volume of KMnO4 consumed for titrating 10 ml of 10/500 or 1/50 ml of H2O2; Eq.Wt of H2O2 = 17.}

_{Applying the formula}  V₁N₁ = V₂N₂ 

        _{N1 = V2N2 / V1}

        _{Normality of H2O2 [N] = V [KMnO4] x 0.1 /  [1/50]}

Strength of Hydrogen Peroxide = V x 0.1 x 50 x 17/ 10 x 3.03 [volumes].

Commercially Hydrogen Peroxide is available in two concentration - viz., 35% and 50%.

In the above calculation please note that 1 ml of 0.1N KMNO4 is equal to 0.0017g 100% H2O2.

To find out the concentration of Hydrogen Peroxide in terms of % strength, follow the simple procedure below:

About 1.5 gram of H₂O₂  is accurately weighed and made up to 250 ml in a standard flask. To 10 ml of this solution, 50 ml distilled water and 30 ml of 20% Sulphuric acid added. The mixture is then titrated against 0.1 KMNO_{4 .} 

_Calculation:

                     _%  H₂O_{2  =} ^{Volume of KMNO4 X N x 17} _{/  Weight of Sample in 10 ml  X 10}