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Testing Strength of Acetic acid, Hydrochloric acid , Sulphuric acid and Oxalic acid

Standardisation of Sulphuric Acid:   Mol Wt: 98.08 & Eq. Wt: 49.0

49 grams/litre of H₂SO₄ gives 1N acid.

Strength Testing of Sulphuric Acid:

Weigh accurately about 1 gram of the acid and transfer to a conical flask with D.D.Water. Add phenolphthalein indicator and titrate against 0.5N NaOH to a permanent pink colour.

% of  H₂SO₄ = (Vol. of NaOH x N of NaOH x 49) / (Wt of Acid x 10)

Standard Norms = 96.5% to 98% w/w.

Acetic Acid Strength Testing:    Mol Wt: 60.05  Eq.Wt: 60.05  Freezing Point:16.6° and Boiling Point:118°C

Weigh accurately about 0.5 gram of the sample and transfer to a conical flask using D.D.Water. The  solution is titrated against 0.5N NaOH using phenolphthalein indicator. The end point is permanent  pink colour.

% of AcOH =

(Vol. of NaOH x Normality of NaOH x 60) / (Wt of acid x 10)

Standard Norms : 96 to 98% w/w

Strength of Citric acid : Eq Wt: 70 Melting Point:153°C

Weigh  accurately 0.5 gram of the sample and dissolve in 50 ml of distilled water. Add phenolphthalein indicator and titrate against 0.5N NaOH to a permanent pink color.

Calculation:

% of acid = (Vol of NaOH x N x 70)/(Wt of acid x 10)

Standard Norms : 95 to 98% w/w.

Strength Testing of Hydro Chloric Acid:   Mol Wt: = 36.46

Weigh accurately 0.5 gram of the acid and transfer to a conical flask with D.D.water. Add phenolphthalein indicator and titrate against 0.5N NaOH to a permanent pink colour.

% of HCl =

(Vol of NaOH x Normality of NaOH x 36.5) / Weight of HCl x 10

Standard Hydrochloric acid strength will be 29 to 35

Tri Sodium Phosphate:   Eq Wt: 82

About 5 grams of dried sample ( heated to 100°C for 2 hours), accurately weighed is dissolved in 50 ml of distilled water. Add 2.5 gram of common salt (vacuum salt) and after to 15°C, the solution is titrated to a distinct red color with 1N HCl, using methyl orange as indicator.

 Calculation:

% of T.S.P. =  (Vol of HCl X Normality of HCl x 82)/(Wt of the sample x 10)

Potassium Permanganate:   Mol Wt: 158.04    Wq.Wt = 31.61

Preparation of Standard solution: 3.161 gram of  KMNO₄ in 500 ml of D.D.water boiled for 30 minutes and made up to 1 litre gives 0.1N solution.

Determination of the strength of KMNO₄:  20 ml of 0.1N Oxalic acid + 20 ml of 1N H₂SO₄ are heated to a warm temp. and titrated against KMNO₄.

V₁N₁ = V₂N₂       N₁= V₂N₂ (0.1 X 20)/burette reading of KMNO₄

Oxalic Acid Strength Testing:  Mol Wt:126.07    Eq.Wt :63.02

Weigh about 0.5 gram of the acid and transfer to a conical flask containing 50 ml of distilled water. Dissolve the acid completely and titrate against 0.5N NaOH using phenolphthalein as indicator.

% of  HOOC-COOH.2H₂O = (Vol of NaOH x N x 63)/ (wt of acid x 10)

Standard Norms = 94 to 98% w/w.

Strength of Sodium Bicarbonate: NaHCO_{3  :}

About 1 gram of the sample accurately weighed is dissolved in distilled water and made up to 250 ml. a 50 ml of the solution is titrated against 0.1N HCl using phenolphthalein as indicator and the reading noted as Y.

Take another 50 ml of the solution and titrate against 0.1N HCl using methyl orange as indicator and the Titre value be X.

Caluculation:

% of Sod.Bicarbonate =

[(X – 2Y) x 0.0084 x 100 x Normality of HCl)]/wt of sample in 50ml

 Standard Norms: 94 to 98%.