In qualitative analysis, when H2S is passed through an aqueous solution of salt acidified with dil. HCl, 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

Question

In qualitative analysis, when H2S is passed through an aqueous solution of salt acidified with dil. HCl, 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 (A) deep blue precipitate of Cu(OH)2  (B) deep blue solution of [Cu(NH3)4]2+  (C) deep blue solution of Cu(NO3)2  (D) deep blue solution of Cu(OH)2.Cu(NO3)2

Tardigrade Admin · Accepted Answer

undersetSalt mathopCuSO4 +H2S xrightarrow[] undersetblack ppt mathopCuS +H2SO4; CuS+2HNO3 xrightarrow[] undersetblue solution mathopCu(NO3)2 +H2S; Cu(NO3)2+4NH3 xrightarrow[] undersetdeep blue solution mathop[Cu(NH3)4]2+ +2NO3-

deep blue precipitate of $C u (O H)_{2}$

deep blue solution of $[C u (N H_{3})_{4}]^{2 +}$

deep blue solution of $C u (N O_{3})_{2}$

deep blue solution of $C u (O H)_{2} . C u (N O_{3})_{2}$

$S a lt C u S O_{4} + H_{2} S b l a c k ppt C u S + H_{2} S O_{4};$ $C u S + 2 H N O_{3} b l u e so l u t i o n C u (N O_{3})_{2} + H_{2} S;$ $C u (N O_{3})_{2} + 4 N H_{3} d ee p b l u e so l u t i o n [C u (N H_{3})_{4}]^{2 +} + 2 N O_{3}^{-}$

Q. In qualitative analysis, when H2​S is passed through an aqueous solution of salt acidified with dil. HCl, 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

deep blue precipitate of Cu(OH)2​

deep blue solution of [Cu(NH3​)4​]2+

deep blue solution of Cu(NO3​)2​

deep blue solution of Cu(OH)2​.Cu(NO3​)2​

SaltCuSO4​​+H2​S​blackpptCuS​+H2​SO4​; CuS+2HNO3​​bluesolutionCu(NO3​)2​​+H2​S; Cu(NO3​)2​+4NH3​​deepbluesolution[Cu(NH3​)4​]2+​+2NO3−​

deep blue precipitate of $C u (O H)_{2}$

deep blue solution of $[C u (N H_{3})_{4}]^{2 +}$

deep blue solution of $C u (N O_{3})_{2}$

deep blue solution of $C u (O H)_{2} . C u (N O_{3})_{2}$

$S a lt C u S O_{4} + H_{2} S b l a c k ppt C u S + H_{2} S O_{4};$ $C u S + 2 H N O_{3} b l u e so l u t i o n C u (N O_{3})_{2} + H_{2} S;$ $C u (N O_{3})_{2} + 4 N H_{3} d ee p b l u e so l u t i o n [C u (N H_{3})_{4}]^{2 +} + 2 N O_{3}^{-}$