The Lassiagne's extract is boiled with dil $\mathrm{HNO}_{3}$ before testing for halogens because,

(D) $\mathrm{Na}_{2} \mathrm{~S}$ and NaCN are decomposed by $\mathrm{HNO}_{3}$

(A) AgCN is soluble in $\mathrm{HNO}_{3}$

(B) Silver halides are soluble in $\mathrm{HNO}_{3}$

(C) $\mathrm{Ag}_{2} \mathrm{~S}$ is soluble in $\mathrm{HNO}_{3}$

JEE Main · 2024 · 30 Jan 2024 · Shift 1 · Practical and Analytical Chemistry

The Lassiagne's extract is boiled with dil

HNO_{3}

before testing for halogens because,

(A)AgCN is soluble in $HNO_{3}$
(B)Silver halides are soluble in $HNO_{3}$
(C) $Ag_{2} S$ is soluble in $HNO_{3}$
(D) $Na_{2} S$ and NaCN are decomposed by $HNO_{3}$ ✓ Correct

Answer: (D)

Solution

Before testing for halides, the sodium-fusion extract is boiled with dilute

HN O_{3}

to destroy any

N a_{2} S

and

NaCN

present (they escape as

H_{2} S

and

HCN

); otherwise these would themselves precipitate with

AgN O_{3}

and give a false-positive halide test.

JEE Main · 2024 · 30 Jan 2024 · Shift 1 · Single correct option

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