c. Optimization of concentration of hydrazine
hydrate
In molybdenum blue method the reducing agent reduces
the phospho molybdic acid thereby giving phospho
molybdenum blue. Hence the formation of phospho
molybdenum is also dependent on the concentration of
reducing agent i.e. hydrazine hydrate. The concentration
of hydrazine was optimized by varying the volumes
of 0.5 M hydrazine hydrate (0.1- 4 mL) in a 25 mL
volumetric flask. A plot of absorbance as a function
of concentration of hydrazine hydrate is shown in
Figure 4. The absorbance shows that with increase in
concentration of hydrazine hydrate, the absorbance
value also increases. After the addition of 1 mL of
hydrazine hydrate the absorbance value remains
constant throughout. So based on this result 1 mL of 0.5
M hydrazine hydrate solution was used throughout the
experiment