NAME: Marianna Christodoulidou -F16183

SAMPLE: Potassium Chloride

1)      IDENTIFICATION REACTIONS OF IONS

-          CATIONS (describe briefly reactions): Potassium (K+)

1.       Dissolve 0.1g of the substance to be examined in 2ml of water R or use 2ml of the
prescribed solution. Add 1ml of sodium carbonate solution R and heta. No precipitate is formed. Add
to the hot solution .05ml of sodium sulphide solution R. No precipitate is formed. Cool in iced
water and 2ml of a 150g/L solution of tartaric acid R. allow to stand. A white crystalline
precipitate is formed.

2.       Dissolve about 40mg of the substance to be examined in 1ml of water R or use 1ml of the
prescribed solution. Add 1ml of dilute acetic acid R and 1ml of a freshly prepared 100g/L solution
of sodium cobaltinitrite R. A yellow or orange-yellow precipitate is formed immediately.


-          ANIONS (describe briefly reactions): Chloride (Cl-)

1.       Dissolve in 2ml of water R a quantity of the substance to be examined equivalent to about
2mg of chloride or 2ml of the prescribed solution. Acidify with dilute nitric acid R and add 0.4ml
of silver nitrate solution R1. Shake and allow to stand. A curdled, white precipitate is formed.
Centrifuge and wash the precipitate with three quantities, each of 1 ml of water R. Carry out this
operation rapidly in subdue light, disregarding the fact that the supernatant solution may not
become perfectly clear. Suspend the precipitate in 2ml of water R and add 1.5ml of ammonia R. The
precipitate dissolves easily with the possible exception of a few large particles which dissolve
slowly.

2.       Introduce into a test-tube a quantity of the substance to be examined equivalent to about
15mg of chloride or the prescribed quantity. Add 0.2g of potassium dichromate R and 1ml of sulfuric
acid R. place a filter-paper strip impregnated with 0.1ml of diphenyl carbazide solution R over the
opening of the test-tube. The paper turns violet-red. The impregnated paper must not come into
contact with the potassium dichromate.




2)      ASSAY

Volumetric solutions: 0.1 M Ag NO3(Silver Nitrate), 0.1M Ammonium thiocyanate

Titre of volumetric solutions: 0.9998 , 0.9897

                                           Titration No.

                                     m [g] (4 decimal places)

                                      Consumption of VS [ml]

                                               ASSAY

                                                1.

                                             1.3256 g

                                               10.56

81.85

                                                2.

                                             1.2988 g

                                               10.87

81.77

                                                3.

                                             1.3004 g

                                               10.35

84.63

                                                4.

                                             1.3006 g

                                               10.54

83.53

                                                                                            Average

82.95

CALCULATION PROCEDURE:

1.       𝑥 (%)= ((V1∗f1)-(V2*F2))∗m∗100)/q

V2= 10.56ml F2=0.9897 M=7.46mg/ml q=1.3256g(1325.6mg) F1=0.9998, V1=25ml

X= ((25*0.9998)-(10.56*0.9897))7.46*100)/1325.6

   =8.1847 X10= 81.8471

2.        𝑥 (%)= ((V1∗f1)-(V2*F2))∗m∗100)/q

= (25*0.9998)-(10.87*0.9897))*7.46*100)/1298.8

   =8.17737 X10= 81.7737


3.     𝑥 (%)= ((V1∗f1)-(V2*F2))∗m∗100)/q

X= ((25*0.9998)-(10.35*0.9897))*7.46*100)/1300.4

   = 8.4625X10= 84.6254


4.       𝑥 (%)= ((V1∗f1)-(V2*F2))∗m∗100)/q

X=((25*0.9998)-(10.54*0.9897)*7.46*100)/1300.6

   = 8.35338X10= 83.5339







STATISTICAL EVALUATION:

Range:
      R = (Xmax-Xmin)= 84.63-81.77 = 2.86

Standard deviation (estimated from range):                         sd = kn*R= K4* R = 0.4857*2.86=
1.3891

Relative standard deviation:                                                        RSD =
(SD/AVERAGE)*100=     (1.3891/82.95)*100= 1.6746




CONCLUSION (does your sample meet/not meet Ph. Eur):

Potassium chloride doesn’t meet pharmacopeia because our content says that potassium chloride is
found in the range of 99% to 100.5%. Our average is 82.945% and it’s not in the range of content
that is given to us.