π¬ Limit Test of Sulphide
π― Aim To perform the limit test for sulphide in a given sample and compare it with the standard solution. π§ͺ Principle Sulphide ions react with lead acetate paper to produce a black or brown stain of lead sulphide (PbS) . Intensity of stain ∝ amount of sulphide present If test solution ΰ€ा stain standard ΰ€Έे darker ΰ€¨ΰ€Ήीं ΰ€Ήै , sample passes the test ✅ ⚗️ Chemical Reaction S²⁻ + Pb²⁺ → PbS ↓ (Black precipitate) π§° Apparatus Nessler cylinders (2) Lead acetate paper Measuring cylinder Test tubes Glass rod 𧴠Reagents Test solution Standard sulphide solution Lead acetate paper Dilute acid (if required) π§π¬ Procedure Take equal volume of test solution in one Nessler cylinder Take standard sulphide solution in another cylinder Suspend lead acetate paper above both cylinders Close the setup and allow reaction for specified time Compare colour/stain intensity π Observation Solution Colour / Stain Standard Light brown/blac...