why it is taken 85ml of hcl for 1litre of solvent according to I.P. while it is 43.02ml when it is calculated?
The reason for the discrepancy between the two values, 85 ml and 43.02 ml, might be due to different concentrations of hydrochloric acid (HCl) being used in the two calculations.
According to the Indian Pharmacopoeia (I.P.), a standard concentration of 85 ml of hydrochloric acid is recommended to be taken for 1 liter of solvent. This concentration corresponds to a specific strength or requirement mentioned in the I.P. for a specific purpose or test.
On the other hand, if you are calculating the required volume of hydrochloric acid based on its known concentration, you will need to consider the molarity or percent by weight/volume of the acid. The molarity is a measure of the concentration of a substance in a solution, while the percent by weight/volume is the amount of solute (HCl) dissolved in a given volume of solution.
To calculate the required volume, you need to know the molarity or percent by weight/volume of the hydrochloric acid, and you can use the formula:
Volume of HCl (ml) = (Desired concentration × Desired volume of solvent) / Concentration of HCl
For example, if you have a 1 M hydrochloric acid solution and you want to prepare 1 liter of solvent using this solution, the calculation will be:
Volume of HCl (ml) = (1 M × 1000 ml) / 1 M = 1000 ml
In this case, the calculated volume is 1000 ml, which is different from the 85 ml mentioned in the I.P. This difference could be due to various factors such as different requirements, test conditions, or specific purposes defined by the I.P.
It's important to note that specific guidelines, regulations, or requirements provided by authoritative sources like the I.P. should be followed strictly to maintain consistency and accuracy in scientific or medical practices.