Practical Chemistry Question 6
Question 6 - 2024 (30 Jan Shift 1)
The Lassiagne’s extract is boiled with dil $\mathrm{HNO}_{3}$ before testing for halogens because,
(1) $\mathrm{AgCN}$ is soluble in $\mathrm{HNO}_{3}$
(2) Silver halides are soluble in $\mathrm{HNO}_{3}$
(3) $\mathrm{Ag}{2} \mathrm{~S}$ is soluble in $\mathrm{HNO}{3}$
(4) $\mathrm{Na}{2} \mathrm{~S}$ and $\mathrm{NaCN}$ are decomposed by $\mathrm{HNO}{3}$
Show Answer
Answer (4)
Solution
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
