In Lassaigne’s test, the formation of a blood-red color indicates the presence of which two elements together?
When both nitrogen and sulphur are present, they form NaSCN, which reacts with Fe³⁺ to give a blood-red color (Fe(SCN)₃).
Ref: NCERT Class 11 Chemistry > Chapter 8: Organic Chemistry - Some Basic Principles and Techniques > Topic: Isomerism - Stereoisomerism - Geometrical and Optical Isomerism