sodiim hydroxide information

Sodium hydroxide

Definition :

Sodium Hydroxide occurs as two forms: the crystal form called Sodium Hydroxide (crystal) and anhydrous form called Sodium Hydroxide (anhydrous). Sodium Hydroxide (crystal) is a mixture of sodium hydroxide (NaOH) and sodium hydroxide monohydrate (NaOH􀅋H2O).

Content:

Sodium Hydroxide (crystal) contains 70.0􀊵75.0% of sodium hydroxide

(NaOH). Sodium Hydroxide (anhydrous) contains not less than 95.0% of sodium

hydroxide (NaOH).

Identification

(1) Sodium Hydroxide solution is strongly alkaline.

(2) Sodium Hydroxide responds to all tests or Sodium Salt as described in the

     Qualitative Tests.

Purity

(1) Clarity and color of solution Colorless, almost clear.

Sample Solution Weigh 50 g of Sodium Hydroxide, and dissolve in freshly boiled

and cooled water to make 250 ml.

Test Solution Measure 5 ml of the sample solution, and mix with 20 ml of water.

(2) Sodium carbonate The content of sodium carbonate (Na2CO3) obtained in

the Assay is not more than 2.0%.

(3) Heavy metals Not more than 30􀀁μg/g as Pb.

Test Solution Measure exactly 5 ml of the sample solution prepared in (1) above,

neutralize by gradually adding diluted hydrochloric acid (1 􀋠 4), and add 2 ml of

diluted acetic acid (1 􀋠 20) and water to make 50 ml.

Control Solution To 3.0 ml of Lead Standard Solution, add 2 ml of diluted acetic

acid (1 􀋠 20) and water to make 50 ml.

(4) Mercury Not more than 0.10 μg/g as Hg.

Test Solution Measure 10 ml of the sample solution prepared in test (1) above,

add 1 ml of potassium permanganate solution (3 􀋠 50) and about 30 ml of water, and shake. Neutralize by gradually adding purified hydrochloric acid, add 5 ml of diluted sulfuric acid (1 􀋠 2), and cool.

Assay

Weigh accurately about 50 g of Sodium Hydroxide, and add freshly boiled and cooled water to make exactly 1,000 ml. Use this solution as the sample solution.Measure exactly 25 ml of the sample solution, add 10 ml of freshly boiled and cooled water, and titrate with 1 mol/l hydrochloric acid (indicator: 1 ml of bromophenol blue TS). After neutralizing, add about 1 ml of 1 mol/l hydrochloric acid, boil for about 5 minutes, and cool. Titrate the excess acid with 0.1 mol/l sodium hydroxide, and determine the volume (a ml) of consumed 1 mol/l hydrochloric acid. Separately, measure exactly 25 ml of the sample solution, transfer into a flask with a ground-glass stopper, and add 25 ml of freshly boiled and cooled water. To the solution, add 10 ml of barium chloride solution (3 􀋠 25), stopper, shake gently, and titrate with 1 mol/l hydrochloric acid (indicator: 1 ml of phenolphthalein TS). Express the consumed volume of 1 mol/l hydrochloric acid as b (ml).

Content of sodium hydroxide (NaOH)

                                        

                                           

Content of sodium carbonate (Na₂CO₃)