Limit Test for Lead (Heavy Metals)
🧪 Limit Test for Lead (Heavy Metals) Subject: Pharmaceutical Inorganic Chemistry Experiment Type: Qualitative Analysis Aim: To carry out the Limit Test for Lead in a given sample using dithizone reagent and to ensure that lead impurities are within the permissible limit as per I.P. standards. ✨ Principle Lead (Pb²⁺) in solution reacts with dithizone (diphenylthiocarbazone) in chloroform. A pink to violet color develops if lead is present. The intensity of color in the sample is compared with that of a standard lead solution. If the test solution shows less or no color compared to the standard, the sample passes the test. Reaction: P b 2 + + D i t h i z o n e ⟶ L e a d - D i t h i z o n a t e C o m p l e x ( P i n k / V i o l e t ) Pb^{2+} + Dithizone \longrightarrow Lead\text{-}Dithizonate\ Complex (Pink/Violet) P b 2 + + D i t hi zo n e ⟶ L e a d - D i t hi zo na t e C o m pl e x ( P ink / Vi o l e t ) ⚗️ Materials Required Test sample ...