In the test for halogens,why is nitric acid a | vedclass

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(B) The sodium fusion extract often contains sodium cyanide $(NaCN)$ and sodium sulphide $(Na_2S)$ if nitrogen and sulphur are present in the organic

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To decompose sodium cyanide and sodium sulphide,which interfere with the test.

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(B) The sodium fusion extract often contains sodium cyanide $(NaCN)$ and sodium sulphide $(Na_2S)$ if nitrogen and sulphur are present in the organic compound. If $AgNO_3$ is added directly,these ions would form precipitates like $AgCN$ and $Ag_2S$,which interfere with the halide test. Adding $HNO_3$ decomposes these species: $NaCN + HNO_3 \rightarrow NaNO_3 + HCN \uparrow$ $Na_2S + 2HNO_3 \rightarrow 2NaNO_3 + H_2S \uparrow$ This ensures that only the halide ions ($Cl^-$,$Br^-$,$I^-$) react with $Ag^+$ to form the characteristic silver halide precipitate.

List-$I$ (Functional group detection)	List-$II$ (Change observed during detection)
$A$. Unsaturation (Baeyer's test)	$I$. Red colour appears
$B$. Alcoholic group (Ceric ammonium nitrate test)	$II$. Silver mirror appears
$C$. Aldehyde group (Tollen's reagent)	$III$. Violet colour appears
$D$. Phenolic group ($FeCl_3$ test)	$IV$. Discharge of pink colour

In the test for halogens,why is nitric acid added to the sodium fusion extract before adding silver nitrate?

Similar Questions

Sodium fusion extract of which compound gives Prussian blue colour with $FeSO_4$?

Assertion : During the test for nitrogen with Lassaigne's extract,on adding $FeCl_3$ solution,sometimes a blood-red coloration is obtained.
Reason : Sulphur is also present along with nitrogen in the organic compound.

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Appearance of blood red colour,on treatment of the sodium fusion extract of an organic compound with $FeSO_4$ in presence of concentrated $H_2SO_4$ indicates the presence of element/s

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