TEXTILE CHEMICAL

HOW TO FIND PERCENTAGE PURITY OF HYDROCHLORIC ACID (HCL)

   Chemical formula         HCL

   Molecular weight          36.5

   Equivalent weight         36.5

   Smell                            Strong with fumes

   Solubility                       Easily soluble in water

   Color                             Color less liquid 

      

     HCL is mainly used for maintaining pH acidic side in textile wet processing. It is also used for diazotisation of fast base for dyeing of azoic colors on cellulosic fiber and fabrics.

    Commercial purity HCL has 37 to 40% purity.

  FIND OUT PERCENTAGE PURITY :

     First weight about 3.0 ml of concentrated HCL in clean and dry weighing bottle with proper care. Then it is transfered to 250 ml measuring flask. Then make total volume 250 ml with distilled water. Now take 10 ml of prepared HCL solution with the help of pipette in conical flask and add 2 - 3 drops of phenolphthalein as an indicator. Now solution remains colorless. Then titrate this solution against 0.1 N NaOH till light pink color is obtained.

  CHEMICAL REACTION :

    HCL       +     NaOH                        ----------------------->  Nacl    +    H2O

   Hydrochloric  Sodium hydroxide         Neutralization       Sodium       Water

        acid                                                                         Chloride

  FORMULA :

  Percentage purity 

   of HCL          =     Equivalent weight of HCL x N. of NaoH x B.R             250

                                ----------------------------------------------------------  x  ----- x 100 

                                 1000 x weight of HCL dissolved in 250 ml                10

              N = Normality of  Sodium hydroxide solution

              B.R = Burete  reading