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(B) In the Lassaigne's test,the sodium extract is acidified with dilute $HNO_{3}$ to decompose any $NaCN$ or $Na_{2}S$ present,which would otherwise i

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$Ag_{2}SO_{4}$ will precipitate,which may be mistaken for $AgCl$.

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(B) In the Lassaigne's test,the sodium extract is acidified with dilute $HNO_{3}$ to decompose any $NaCN$ or $Na_{2}S$ present,which would otherwise interfere with the test.If dilute $H_{2}SO_{4}$ is used instead of $HNO_{3}$,$Ag^{+}$ ions from $AgNO_{3}$ will react with $SO_{4}^{2-}$ ions to form $Ag_{2}SO_{4}$.$2AgNO_{3} + H_{2}SO_{4} \rightarrow Ag_{2}SO_{4} + 2HNO_{3}$Since $Ag_{2}SO_{4}$ has low solubility,it forms a white precipitate that can be incorrectly identified as $AgCl$,leading to a false positive result.

For testing halogens in an organic compound with $AgNO_{3}$ solution,sodium extract (Lassaigne's test) is acidified with dilute $HNO_{3}$. What will happen if a student acidifies the extract with dilute $H_{2}SO_{4}$ in place of dilute $HNO_{3}$?

Similar Questions

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