Page 85 - PC 101 practical notes 24-25..

MANSOURA NATIONAL UNIVERSIY
PHARM D- CLINICAL PHARMACY LEVEL I PHARM. ANAL. CHEM. I (PC 101)

C Ca al lc cu ul la at ti io on ns s : :

st
In this exp., the equivalence factor (F) can be calculated on 0.05 N AgNO3 (1 standard
nd
"25 ml") OR on 0.01 N NH4SCN (2 standard "titrant") but it is preferred to be calculated
st
on the 1 standard.
If (F) is calculated on the 1 standard (0.05 N AgNO3):
st
Equivalence factor (F):

1 AgNO 3 ≡ 1 KBr
standard sample

1 x M.W. of KBr x 0.05
each ml of 0.05 N AgNO3 ≡ ≡ .......... g KBr
1 x 1000

Calculation of concentration:

0.05 N 0.01 N 0.05 N

[25 – E.P. ( . 0 01 )] x F x 1000
Concn. = . 0 05 = .......... g/L
10

If (F) is calculated on the 2 standard (0.01 N NH4SCN):
nd
Equivalence factor (F):

1 NH 4SCN ≡ 1 KBr
standard sample

1 x M.W. of KBr x 0.01
each ml of 0.01 N NH 4SCN ≡ ≡ .......... g KBr
1 x 1000

Calculation of concentration:

0.05 N 0.01 N 0.01 N

[25 ( . 0 05 ) – E.P.] x F x 1000
Concn. = . 0 01 = .......... g/L
10

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