The Lassaigne's extract is boiled with conc. HNO3 while testing for halogens. By doing so it

Question

The Lassaigne's extract is boiled with conc. HNO3 while testing for halogens. By doing so it (A) helps in the precipitation of AgCl (B) increases the solubility product of AgCl (C) increases the concentration of NO-3 ions (D) decomposes Na2S and NaCN, if formed

Tardigrade Admin · Accepted Answer

Na2S and NaCN, if present in the extract, will be decomposed to H2S and HCN by HNO3 . NaCN + HNO3 arrow NaNO3 + HCN Na2S + 2HNO3 arrow 2NaNO3 + H2S These will escape from the solution and will not interfere with the test for halogens.

Q. The Lassaigne's extract is boiled with conc. $H N O_{3}$ while testing for halogens. By doing so it

helps in the precipitation of $A g Cl$

increases the solubility product of $A g Cl$

increases the concentration of $N O_{3}^{-}$ ions

decomposes $N a_{2} S$ and $N a CN$ , if formed

Na $_{2}$ S and NaCN, if present in the extract, will be
decomposed to H $_{2}$ S and HCN by HNO $_{3}$ .
NaCN + HN $O_{3}$ $\to$ NaN $O_{3}$ + HCN
Na $_{2}$ S + 2HNO $_{3}$ $\to$ 2NaN $O_{3}$ + H $_{2}$ S
These will escape from the solution and will not
interfere with the test for halogens.

Q. The Lassaigne's extract is boiled with conc. HNO3​ while testing for halogens. By doing so it

helps in the precipitation of AgCl

increases the solubility product of AgCl

increases the concentration of NO3−​ ions

decomposes Na2​S and NaCN, if formed