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Byju's Answer

Standard XII

Chemistry

Introduction to Oxidation and Reduction

In qualitativ...

Question

In qualitative analysis, when $H_{2} S$ is passed through an aqueous solution of salt acidified with dil. HCI, a black precipitate is obtained. On boiling the precipitate with $d i l . H N O_{3}$ , it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives

Deep blue precipitate of

C u (O H)_{2}

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Deep blue solution of

[C u (N H_{3})_{4}]^{2 +}

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Deep blue solution of

C u (N O_{3})_{2}

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Deep blue solution of

C u (O H)_{2} \cdot C u (N O_{3})_{2}

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Solution

The correct option is B Deep blue solution of $[C u (N H_{3})_{4}]^{2 +}$
$C u S O_{4} + H_{2} S ⟶ C u S b l a c k p p t + H_{2} S O_{4}$
$C u S + 2 H N O_{3} ⟶ C u (N O_{3})_{2} b l u e s o l u t i o n + H_{2} S$
$C u (N O_{3})_{2} + 4 N H_{3} ⟶ C u (N H_{3})_{4}]^{2 +} d e e p b l u e s o l u t i o n + 2 N O_{3}^{-}$

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Similar questions

Q. A black coloured compound

(A)

on reaction with dilute

H_{2} S O_{4}

gives a gas

(B)

which on passing in a solution of an acid

(C)

gives a white turbidity

(D)

. Gas

(B)

when passed in an acidified solution of a compound

(E)

gives a precipitate

(F)

soluble in dil.

H N O_{3}

. After boiling this solution when an excess of

N H_{4} O H

is added, a blue coloured compound

(G)

is formed. To this solution on addition of acetic acid and aqueous

K_{4} [F e (C N)_{6}]

a chocolate precipitate

(H)

is obtained. On addition of an aqueous soluion of

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to an aqueous solution of

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, a white precipitate insoluble in

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Q. Aqueous solution of light greenish crystalline compound reacts with potassium ferricyanide to give a deep blue coloured solution or precipitate. Its chemical formula is:

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Q. An aqueous solution of a gas (X) shows the following reactions :
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Q. An aqueous solution of a gas

(X)

shows the following reactions.
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C u S O_{4}

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In qualitative analysis, when H2S is passed through an aqueous solution of salt acidified with dil. HCI, a black precipitate is obtained. On boiling the precipitate with dil.HNO3, it forms a solution of blue colour. Addition of excess of aqueous solution of ammonia to this solution gives

The correct option is B Deep blue solution of [Cu(NH3)4]2+CuSO4+H2S⟶CuSblackppt+H2SO4CuS+2HNO3⟶Cu(NO3)2bluesolution+H2SCu(NO3)2+4NH3⟶Cu(NH3)4]2+deepbluesolution+2NO−3