Why is nitric acid (HNO_3) added to sodium ex | vedclass

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Question

(B) The sodium extract often contains sodium cyanide $(NaCN)$ and sodium sulphide $(Na_2S)$ along with sodium halides $(NaX)$.If these are not removed

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To decompose sodium cyanide $(NaCN)$ and sodium sulphide $(Na_2S)$ if present.

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(B) The sodium extract often contains sodium cyanide $(NaCN)$ and sodium sulphide $(Na_2S)$ along with sodium halides $(NaX)$.If these are not removed,they would react with silver nitrate $(AgNO_3)$ to form silver cyanide $(AgCN)$ and silver sulphide $(Ag_2S)$,which are also precipitates and would interfere with the test for halogens.Nitric acid $(HNO_3)$ is added to decompose these interfering ions into volatile gases like hydrogen cyanide $(HCN)$ and hydrogen sulphide $(H_2S)$,which are then boiled off.Therefore,the correct reason is to decompose sodium cyanide and sodium sulphide if present.

List-$I$ (Test/Reagents/Observation)	List-$II$ (Species detected)
$(a)$ Lassaigne's Test	$(i)$ Carbon
$(b)$ $Cu(II)$ oxide	$(ii)$ Sulphur
$(c)$ Silver nitrate	$(iii)$ $N, S, P,$ and halogen
$(d)$ The sodium fusion extract gives black precipitate with acetic acid and lead acetate	$(iv)$ Halogen specifically

List-$I$ Element detected	List-$II$ Reagent used/Product formed
$A$. Nitrogen	$I$. $Na_2[Fe(CN)_5NO]$
$B$. Sulphur	$II$. $AgNO_3$
$C$. Phosphorus	$III$. $Fe_4[Fe(CN)_6]_3$
$D$. Halogen	$IV$. $(NH_4)_2MoO_4$

Why is nitric acid $(HNO_3)$ added to sodium extract before adding silver nitrate $(AgNO_3)$ for testing halogens?

Similar Questions

In $Kjeldahl’s$ method,$CuSO_4$ acts as

Discuss the chemistry of Lassaigne's test.

Match List-$I$ with List-$II$.

List-$I$ Element detected List-$II$ Reagent used/Product formed

$A$. Nitrogen $I$. $Na_2[Fe(CN)_5NO]$

$B$. Sulphur $II$. $AgNO_3$

$C$. Phosphorus $III$. $Fe_4[Fe(CN)_6]_3$

$D$. Halogen $IV$. $(NH_4)_2MoO_4$

Choose the correct answer from the options given below:

The sodium fusion extract is boiled with concentrated nitric acid while testing for halogens. By doing so,it

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