Question

The Lassiagne's extract is boiled with dil \(HNO_3\) before testing for halogens because,

(1) AgCN is soluble in \(HNO_3\)

(2) Silver halides are soluble in \(HNO_3\)

(3) \(Ag_2S\) is soluble in \(HNO_3\)

(4) \(Na_2S\) and NaCN are decomposed by \(HNO_3\)

Answer 1

(4) \(Na_2S\) and NaCN are decomposed by \(HNO_3\)

If nitrogen or sulphur is also present in the compound, the sodium fusion extract is first boiled with concentrated nitric acid to decompose cyanide or sulphide of sodium during Lassaigne's test.