Answer :
(D) [tex](NH_{4})_{2}S[/tex] (C) [tex]Ba(NO_{3})_{2}[/tex] (B) [tex]CuCl_{2}[/tex]
(A) [tex]K_{2}SO_{4}[/tex] _ [tex]BaSO_{4}[/tex] _
(B) [tex]CuCl_{2}[/tex] [tex]Cu_{2}S_{2}[/tex] _
(C) [tex]Ba(NO_{3})_{2}[/tex] BaS
Explanation :
(1) Reaction for A + B
[tex]K_{2}SO_{4}[/tex] + [tex]CuCl_{2}\rightarrow[/tex] 2KCl + [tex]CuSO_{4}[/tex]
In this reaction, there is no precipitate formed as the products are souble.
(2) Reaction for A + C
[tex]K_{2}SO_{4}[/tex] + [tex]Ba(NO_{3})_{2}\rightarrow[/tex] [tex]BaSO_{4}[/tex] + [tex]KNO_{3}[/tex]
In this reaction, [tex]BaSO_{4}[/tex] is formed as precipitate as it do not dissolve.
(3) Reaction for A + D
[tex]K_{2}SO_{4}[/tex] + [tex](NH_{4})_{2}S\rightarrow[/tex] [tex]K_{2}S[/tex] + [tex](NH_{4})_{2}SO_{4}[/tex]
In this reaction, there is no precipitate formed as the products are souble.
(4) Reaction for B + D
[tex]2CuCl_{2}[/tex] + [tex]2(NH_{4})_{2}S\rightarrow[/tex] [tex]4NH_{4}Cl+Cu_{2}S_{2}[/tex]
In this reaction, [tex]Cu_{2}S_{2}[/tex] is formed as precipitate as it do not dissolve.
(5) Reaction for B + C
[tex]CuCl_{2}[/tex] + [tex]Ba(NO_{3})_{2}\rightarrow[/tex] [tex]BaCl_{2}[/tex] + [tex]Cu(NO_{3})_{2}[/tex]
In this reaction, there is no precipitate formed as the products are souble.
(6) Reaction for C + D
[tex]Ba(NO_{3})_{2}[/tex] + [tex](NH_{4})_{2}S\rightarrow[/tex] BaS + [tex]2NH_{4}NO_{3}[/tex]
In this reaction, BaS is formed as precipitate as it do not dissolve.
