Preparation of 0.005M sulfuric Acid :

Normality =molarity x Basicity

for sulphuric acid 1 molar = 2 Normal

18 Molar = 36N

N        = 18 x 2 =36

 = 36N

18 Molar = 36N

 1000 x 0.1 N  =     100      = 2.777 ml = 2.8ml 

        36N                 36 

For 0.1N--------------2.8ml of sulfuric Acid is required(in 1000ml) =0.05molar

0.01N =0.005molar

        2.8 ml  of sulphuric acid / lit---------------    = 0.05m

        0.28 ml of sulphuric acid / lit--------------- = 0.005m

      0.028ml(0.03ml) of sulfuric acid for 100ml =0.005m

For standard 1000ppm K₂Cr₂O_7:

Take 1 gm of K₂Cr₂O₇ in 1000ml of standard vol flask and make up with only distill water

Note: For dilutions only, we are adding 0.005M Sulphuric acid, for standard 1000ppm we are not adding 0.005M Sulphuric acid

Preparation of 60ppm of K₂Cr₂O₇ :

0.06 gm in 1000ml is 60ppm

0.06gm---------------------1000ml (60ppm)

?-------------------------250ml

250 ´0.0 6  = 0.015gm (60ppm)

   1000

0.015gm in 250 ml std volumetric flask (60ppm) and fill with 0.005M sulfuric Acid

Preparation of 40ppm of K₂Cr₂O₇ :

0.04 gm in 1000ml is 40ppm

0.04gm---------------------1000ml (40ppm)

?-------------------------250ml

250 ´0.0 4  = 0.01gm (40ppm)

   1000

0.01gm in 250 ml std volumetric flask (40ppm) and fill with 0.005M sulfuric Acid

Preparation of 20ppm of K₂Cr₂O₇ :

0.02 gm in 1000ml is 20ppm

0.02gm---------------------1000ml (20ppm)

?-------------------------250ml

250 ´ 0.02  = 0.005 (20ppm)

   1000

0.005gm in 250 ml std volumetric flask (20ppm) and fill with 0.005M sulfuric Acid

Dilution preperation:

Available ppm(1000ppm)   X        x(vol to be transferred) = (60ppm) req ppm X(100ml)req vol

                                                              x= 60X 100     =  6000     = 6ml

1000                           1000

Take 6ml of 1000ppm in 100ml of std vol flask = 60 ppm and add 0.03ml H2S04