Q. The Lassaigne's extract is boiled with conc. HNO₃ while testing for halogens. By doing so it
A) Increases the concentration of NO₃⁻ ions
B) Decomposes Na₂S and NaCN, if formed
C) Helps in the precipitation of AgCl
D) Increases the solubility product of AgCl
Explanation
[Solution from source] If N or S is present, Na₂S and NaCN are in the Lassaigne extract and would give black Ag₂S or white AgCN with AgNO₃, interfering with the halide test. Boiling with HNO₃ decomposes them (releasing H₂S and HCN). It does not change the solubility product of AgCl. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.