SATHEE: Qualitative Analysis - Result Question 62

Qualitative Analysis - Result Question 62

####65. An orange solid $A$ on heating gave a green residue $B$ , a colourless gas $C$ and water vapour. The dry gas $C$ on passing over heated $M g$ gave a white solid $D . D$ on reaction with water gave a gas $E$ which formed dense white fumes with $H C l$ . Identify $A$ to $E$ and give the reaction involved.

(1993, 3M)

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Solution:

$\underset{Orange solid}{A} \overset{Δ}{⟶} \underset{Green}{B ↓} + \underset{Colourless}{C ↑} + H_{2} O (v) ↑$

$C + M g ⟶ D (white solid)$

$D + H_{2} O ⟶ E (g) \overset{H C l}{\to}$ White fumes.

Hence, $E$ must be ammonia gas so $D$ must be $M g_{3} N_{2}$ and $C$ is $N_{2} (g)$ . This $N_{2}$ is obtained on strong heating of ${(N H_{4})}_{2} C r_{2} O_{7}$ because ${(N H_{4})}_{2} C r_{2} O_{7}$ is orange solid and produces green $C r_{2} O_{3}$ residue on heating.

$\begin{aligned} {(N H_{4})}_{2} C r_{2} O_{7} \overset{Δ}{⟶} C r_{2} O_{3} + N_{2} + 4 H_{2} O \\ Orange (A) Green (B) C \\ N_{2} + M g \overset{Δ}{⟶} \underset{D}{M g_{3} N_{2}} \to_{E}^{H_{2} O} \underset{N H_{3}}{N g_{2} (O H)_{2}} \\ N H_{3} + H C l ⟶ N H_{4} C l (white fumes) \\ E \end{aligned}$

Qualitative Analysis - Result Question 62

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Qualitative Analysis - Result Question 62

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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